<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2025 Workiva-->
<!--r:e58d44a6-0a9a-41df-80c9-9800856ba420,g:c5aaacc8-a34e-492f-983f-eff325ea271c-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.sandisk.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS" xlink:type="simple" xlink:href="sndk-20251003.xsd#CONDENSEDCONSOLIDATEDBALANCESHEETS"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_b3f978f3-9c65-4f94-8d38-3b6df8450bc7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_83ab8d17-cfb4-4621-be20-c7695f1a1e16" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_b3f978f3-9c65-4f94-8d38-3b6df8450bc7" xlink:to="loc_us-gaap_StatementTable_83ab8d17-cfb4-4621-be20-c7695f1a1e16" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2ff17439-e1c7-4f83-ba44-8062d03fdb8e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_83ab8d17-cfb4-4621-be20-c7695f1a1e16" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2ff17439-e1c7-4f83-ba44-8062d03fdb8e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_2ff17439-e1c7-4f83-ba44-8062d03fdb8e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2ff17439-e1c7-4f83-ba44-8062d03fdb8e" xlink:to="loc_us-gaap_RelatedPartyDomain_2ff17439-e1c7-4f83-ba44-8062d03fdb8e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_d81c8a90-9e21-4d1c-ad39-e30709b2968b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_2ff17439-e1c7-4f83-ba44-8062d03fdb8e" xlink:to="loc_us-gaap_RelatedPartyDomain_d81c8a90-9e21-4d1c-ad39-e30709b2968b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_058336c3-08b9-4c45-a438-4065b071f053" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_d81c8a90-9e21-4d1c-ad39-e30709b2968b" xlink:to="loc_us-gaap_NonrelatedPartyMember_058336c3-08b9-4c45-a438-4065b071f053" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_c733ad9e-143d-4c62-8aef-aa41611aa699" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_d81c8a90-9e21-4d1c-ad39-e30709b2968b" xlink:to="loc_us-gaap_RelatedPartyMember_c733ad9e-143d-4c62-8aef-aa41611aa699" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_bb0999ec-6fd2-40b3-82fa-20eec7c72860" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b3f978f3-9c65-4f94-8d38-3b6df8450bc7" xlink:to="loc_us-gaap_AssetsAbstract_bb0999ec-6fd2-40b3-82fa-20eec7c72860" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_47a51748-e807-4327-80d8-a157d8d364fd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bb0999ec-6fd2-40b3-82fa-20eec7c72860" xlink:to="loc_us-gaap_AssetsCurrentAbstract_47a51748-e807-4327-80d8-a157d8d364fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_7e7f547b-f2a4-4f50-abdf-a7bcd519d7ca" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_47a51748-e807-4327-80d8-a157d8d364fd" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_7e7f547b-f2a4-4f50-abdf-a7bcd519d7ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_c1a67266-6fe2-4a30-9667-b20849228e6d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_47a51748-e807-4327-80d8-a157d8d364fd" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_c1a67266-6fe2-4a30-9667-b20849228e6d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_d6bc831d-df1d-4f5d-8857-a040f2dd74ca" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_47a51748-e807-4327-80d8-a157d8d364fd" xlink:to="loc_us-gaap_InventoryNet_d6bc831d-df1d-4f5d-8857-a040f2dd74ca" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesReceivable_4dce013d-6a2f-45da-85a5-0a555e4ec425" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxesReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_47a51748-e807-4327-80d8-a157d8d364fd" xlink:to="loc_us-gaap_IncomeTaxesReceivable_4dce013d-6a2f-45da-85a5-0a555e4ec425" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsCurrent_17a710a0-9659-4b21-b53d-192f462a8252" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_47a51748-e807-4327-80d8-a157d8d364fd" xlink:to="loc_us-gaap_OtherAssetsCurrent_17a710a0-9659-4b21-b53d-192f462a8252" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_4834d737-4d15-4518-b8c3-934ea64bcc56" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_47a51748-e807-4327-80d8-a157d8d364fd" xlink:to="loc_us-gaap_AssetsCurrent_4834d737-4d15-4518-b8c3-934ea64bcc56" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsNoncurrentAbstract_04a970dd-f552-4edc-8199-dc9ab7154669" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bb0999ec-6fd2-40b3-82fa-20eec7c72860" xlink:to="loc_us-gaap_AssetsNoncurrentAbstract_04a970dd-f552-4edc-8199-dc9ab7154669" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_35275aa5-b7d9-4306-92e3-2e9969db6528" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_04a970dd-f552-4edc-8199-dc9ab7154669" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_35275aa5-b7d9-4306-92e3-2e9969db6528" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_NotesReceivableAndInvestmentsInRelatedPartiesNoncurrent_41f9d7af-14ad-4c8d-a7af-7d6240307a1f" xlink:href="sndk-20251003.xsd#sndk_NotesReceivableAndInvestmentsInRelatedPartiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_04a970dd-f552-4edc-8199-dc9ab7154669" xlink:to="loc_sndk_NotesReceivableAndInvestmentsInRelatedPartiesNoncurrent_41f9d7af-14ad-4c8d-a7af-7d6240307a1f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_b814de94-ab5e-4b7f-b397-66a7ebaa3534" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_04a970dd-f552-4edc-8199-dc9ab7154669" xlink:to="loc_us-gaap_Goodwill_b814de94-ab5e-4b7f-b397-66a7ebaa3534" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_68038587-0d74-4ffb-86a3-f1a28ed9918d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_04a970dd-f552-4edc-8199-dc9ab7154669" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_68038587-0d74-4ffb-86a3-f1a28ed9918d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesReceivableNoncurrent_7c12c4c0-5de9-4432-8ddd-b1134143568e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxesReceivableNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_04a970dd-f552-4edc-8199-dc9ab7154669" xlink:to="loc_us-gaap_IncomeTaxesReceivableNoncurrent_7c12c4c0-5de9-4432-8ddd-b1134143568e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_ae973a72-5fbd-4923-b449-4d787a2f3437" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_04a970dd-f552-4edc-8199-dc9ab7154669" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_ae973a72-5fbd-4923-b449-4d787a2f3437" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_42fa17cb-d0dd-4571-8026-616bdefd3367" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_bb0999ec-6fd2-40b3-82fa-20eec7c72860" xlink:to="loc_us-gaap_Assets_42fa17cb-d0dd-4571-8026-616bdefd3367" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_456373dd-01a2-45e6-9fe8-3e2517beb42d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b3f978f3-9c65-4f94-8d38-3b6df8450bc7" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_456373dd-01a2-45e6-9fe8-3e2517beb42d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_56009ef1-4536-4469-b6ea-ed55fb9c90e4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_456373dd-01a2-45e6-9fe8-3e2517beb42d" xlink:to="loc_us-gaap_LiabilitiesAbstract_56009ef1-4536-4469-b6ea-ed55fb9c90e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_819fda56-ed17-4b54-999b-198ada60989d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_56009ef1-4536-4469-b6ea-ed55fb9c90e4" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_819fda56-ed17-4b54-999b-198ada60989d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_76d6871a-27f5-4508-a06a-ee9de3b265f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_819fda56-ed17-4b54-999b-198ada60989d" xlink:to="loc_us-gaap_AccountsPayableCurrent_76d6871a-27f5-4508-a06a-ee9de3b265f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_827be63e-c48b-4da0-a036-bc41da2919b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_819fda56-ed17-4b54-999b-198ada60989d" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_827be63e-c48b-4da0-a036-bc41da2919b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_293adf1a-2c10-473e-aefd-1f6b55c490aa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_819fda56-ed17-4b54-999b-198ada60989d" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_293adf1a-2c10-473e-aefd-1f6b55c490aa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedIncomeTaxesCurrent_99c8f760-a31d-44d7-b0ae-4e9a2109b17a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedIncomeTaxesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_819fda56-ed17-4b54-999b-198ada60989d" xlink:to="loc_us-gaap_AccruedIncomeTaxesCurrent_99c8f760-a31d-44d7-b0ae-4e9a2109b17a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_94a4a0b7-e4d1-49d4-b43b-b7b49c95fc6e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_819fda56-ed17-4b54-999b-198ada60989d" xlink:to="loc_us-gaap_LongTermDebtCurrent_94a4a0b7-e4d1-49d4-b43b-b7b49c95fc6e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_584cb2e8-5c41-4278-bd81-473085725be7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_819fda56-ed17-4b54-999b-198ada60989d" xlink:to="loc_us-gaap_LiabilitiesCurrent_584cb2e8-5c41-4278-bd81-473085725be7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesNoncurrentAbstract_460451dd-5a0d-4bb6-8d21-42fb381b0ccc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_56009ef1-4536-4469-b6ea-ed55fb9c90e4" xlink:to="loc_us-gaap_LiabilitiesNoncurrentAbstract_460451dd-5a0d-4bb6-8d21-42fb381b0ccc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_17713181-4577-4b1d-9ca2-6bd0c028426f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_460451dd-5a0d-4bb6-8d21-42fb381b0ccc" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_17713181-4577-4b1d-9ca2-6bd0c028426f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_461ac193-50bd-4192-a1c2-713f769de4ba" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_460451dd-5a0d-4bb6-8d21-42fb381b0ccc" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_461ac193-50bd-4192-a1c2-713f769de4ba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_0810c188-9c8a-4b1f-832e-05f1db85000b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_460451dd-5a0d-4bb6-8d21-42fb381b0ccc" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_0810c188-9c8a-4b1f-832e-05f1db85000b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_33669ff5-e466-495e-bab8-93996d340882" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_56009ef1-4536-4469-b6ea-ed55fb9c90e4" xlink:to="loc_us-gaap_Liabilities_33669ff5-e466-495e-bab8-93996d340882" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_f013347e-f61c-4c0d-8949-5bfdda1913e7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_56009ef1-4536-4469-b6ea-ed55fb9c90e4" xlink:to="loc_us-gaap_CommitmentsAndContingencies_f013347e-f61c-4c0d-8949-5bfdda1913e7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_8eee89f6-3998-466e-828e-d04af9ef3d7d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_56009ef1-4536-4469-b6ea-ed55fb9c90e4" xlink:to="loc_us-gaap_StockholdersEquityAbstract_8eee89f6-3998-466e-828e-d04af9ef3d7d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_bf2326a7-3fa4-4f75-a3d3-eed486c8b1f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_8eee89f6-3998-466e-828e-d04af9ef3d7d" xlink:to="loc_us-gaap_CommonStockValue_bf2326a7-3fa4-4f75-a3d3-eed486c8b1f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_30c02f64-467b-4041-8dc2-0d42a3dae0db" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_8eee89f6-3998-466e-828e-d04af9ef3d7d" xlink:to="loc_us-gaap_AdditionalPaidInCapital_30c02f64-467b-4041-8dc2-0d42a3dae0db" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_9ef708d3-dd44-4b2d-8dee-471eced0e522" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_8eee89f6-3998-466e-828e-d04af9ef3d7d" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_9ef708d3-dd44-4b2d-8dee-471eced0e522" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_23e595f6-783b-4719-a2b7-893a4ba202c5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_8eee89f6-3998-466e-828e-d04af9ef3d7d" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_23e595f6-783b-4719-a2b7-893a4ba202c5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_d02dbe9b-3d30-4bdf-be7e-ccc5f36611bf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_8eee89f6-3998-466e-828e-d04af9ef3d7d" xlink:to="loc_us-gaap_StockholdersEquity_d02dbe9b-3d30-4bdf-be7e-ccc5f36611bf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_fc5b2359-09de-41ab-a6c5-8e75a367f32c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_456373dd-01a2-45e6-9fe8-3e2517beb42d" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_fc5b2359-09de-41ab-a6c5-8e75a367f32c" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" xlink:type="simple" xlink:href="sndk-20251003.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_31fbbc4d-05ec-4a69-af1b-94afd4ff1d93" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_0988eec3-c3df-44bf-886e-2ed49fe09cc6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_31fbbc4d-05ec-4a69-af1b-94afd4ff1d93" xlink:to="loc_us-gaap_StatementTable_0988eec3-c3df-44bf-886e-2ed49fe09cc6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_d5a9d27e-16be-4409-8b02-7325073afcf4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0988eec3-c3df-44bf-886e-2ed49fe09cc6" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_d5a9d27e-16be-4409-8b02-7325073afcf4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_d5a9d27e-16be-4409-8b02-7325073afcf4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_d5a9d27e-16be-4409-8b02-7325073afcf4" xlink:to="loc_us-gaap_EquityComponentDomain_d5a9d27e-16be-4409-8b02-7325073afcf4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_735abde6-e873-4f04-a565-9ebea3809662" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_d5a9d27e-16be-4409-8b02-7325073afcf4" xlink:to="loc_us-gaap_EquityComponentDomain_735abde6-e873-4f04-a565-9ebea3809662" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_54f09d96-cbb8-42dc-8d10-1a2c4395260e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_735abde6-e873-4f04-a565-9ebea3809662" xlink:to="loc_us-gaap_CommonStockMember_54f09d96-cbb8-42dc-8d10-1a2c4395260e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_f64600fd-37ed-4136-85bc-127328825085" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_735abde6-e873-4f04-a565-9ebea3809662" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_f64600fd-37ed-4136-85bc-127328825085" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_3b231688-2fb3-466e-b0a4-d1f930dad6c0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_735abde6-e873-4f04-a565-9ebea3809662" xlink:to="loc_us-gaap_RetainedEarningsMember_3b231688-2fb3-466e-b0a4-d1f930dad6c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_b301b14e-9862-4a6c-aba8-eb28f455b76e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_735abde6-e873-4f04-a565-9ebea3809662" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_b301b14e-9862-4a6c-aba8-eb28f455b76e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_ParentCompanyNetInvestmentMember_7788baa1-f6a6-4105-8a5e-8869c152af06" xlink:href="sndk-20251003.xsd#sndk_ParentCompanyNetInvestmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_735abde6-e873-4f04-a565-9ebea3809662" xlink:to="loc_sndk_ParentCompanyNetInvestmentMember_7788baa1-f6a6-4105-8a5e-8869c152af06" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_010928a2-63c2-4c22-95f4-b9d3e857017d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31fbbc4d-05ec-4a69-af1b-94afd4ff1d93" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_010928a2-63c2-4c22-95f4-b9d3e857017d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_ca912964-feee-44b8-a5c0-bb925ef221ec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_010928a2-63c2-4c22-95f4-b9d3e857017d" xlink:to="loc_us-gaap_SharesOutstanding_ca912964-feee-44b8-a5c0-bb925ef221ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_3a4028f4-31b1-477e-81b8-c44446cb6620" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_010928a2-63c2-4c22-95f4-b9d3e857017d" xlink:to="loc_us-gaap_StockholdersEquity_3a4028f4-31b1-477e-81b8-c44446cb6620" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_83f85f25-8d01-4209-873b-1bcf9b1511a0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_010928a2-63c2-4c22-95f4-b9d3e857017d" xlink:to="loc_us-gaap_NetIncomeLoss_83f85f25-8d01-4209-873b-1bcf9b1511a0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_dc847a3b-607d-4030-9704-8af55e8146bc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_010928a2-63c2-4c22-95f4-b9d3e857017d" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_dc847a3b-607d-4030-9704-8af55e8146bc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation_beccf6e1-b364-485a-9c89-f7e68e6379d4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_010928a2-63c2-4c22-95f4-b9d3e857017d" xlink:to="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation_beccf6e1-b364-485a-9c89-f7e68e6379d4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax_73d3f482-2356-4183-b17b-70bd8254a9a5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_010928a2-63c2-4c22-95f4-b9d3e857017d" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax_73d3f482-2356-4183-b17b-70bd8254a9a5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax_433a351b-e806-4268-8caa-35e7f8b3b173" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_010928a2-63c2-4c22-95f4-b9d3e857017d" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTax_433a351b-e806-4268-8caa-35e7f8b3b173" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_2546005f-fd80-499e-a759-1520e009d0f7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_010928a2-63c2-4c22-95f4-b9d3e857017d" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_2546005f-fd80-499e-a759-1520e009d0f7" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_TransfersInTransfersOutFromParentStockholdersEquity_93a0a7cb-da0d-4499-afed-a50c99d353a8" xlink:href="sndk-20251003.xsd#sndk_TransfersInTransfersOutFromParentStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_010928a2-63c2-4c22-95f4-b9d3e857017d" xlink:to="loc_sndk_TransfersInTransfersOutFromParentStockholdersEquity_93a0a7cb-da0d-4499-afed-a50c99d353a8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_3daee474-0338-41dd-814e-61037d96ddc6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_580a8427-c1e1-4870-9680-535cf3d7c8ea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/OrganizationandBasisofPresentationDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#OrganizationandBasisofPresentationDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/OrganizationandBasisofPresentationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestLineItems_d38eebf8-63b9-463d-974c-b60efd5b21c3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MinorityInterestLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestTable_1ef88463-0855-4de2-bf2a-2416a748fb48" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MinorityInterestTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_MinorityInterestLineItems_d38eebf8-63b9-463d-974c-b60efd5b21c3" xlink:to="loc_us-gaap_MinorityInterestTable_1ef88463-0855-4de2-bf2a-2416a748fb48" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_73bd7d74-cd55-4796-9750-926b7f3f432b" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_MinorityInterestTable_1ef88463-0855-4de2-bf2a-2416a748fb48" xlink:to="loc_dei_LegalEntityAxis_73bd7d74-cd55-4796-9750-926b7f3f432b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_73bd7d74-cd55-4796-9750-926b7f3f432b_default" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_73bd7d74-cd55-4796-9750-926b7f3f432b" xlink:to="loc_dei_EntityDomain_73bd7d74-cd55-4796-9750-926b7f3f432b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_bcb55c1e-2ec2-4028-8e16-8b8b76f16471" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_73bd7d74-cd55-4796-9750-926b7f3f432b" xlink:to="loc_dei_EntityDomain_bcb55c1e-2ec2-4028-8e16-8b8b76f16471" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_WesternDigitalCorporationMember_25dcba5c-dc8b-47d7-8d9b-9e45f71b82a9" xlink:href="sndk-20251003.xsd#sndk_WesternDigitalCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_bcb55c1e-2ec2-4028-8e16-8b8b76f16471" xlink:to="loc_sndk_WesternDigitalCorporationMember_25dcba5c-dc8b-47d7-8d9b-9e45f71b82a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_c8ea3be7-7642-4501-902f-1c77fcd55362" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_MinorityInterestTable_1ef88463-0855-4de2-bf2a-2416a748fb48" xlink:to="loc_srt_OwnershipAxis_c8ea3be7-7642-4501-902f-1c77fcd55362" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_c8ea3be7-7642-4501-902f-1c77fcd55362_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_c8ea3be7-7642-4501-902f-1c77fcd55362" xlink:to="loc_srt_OwnershipDomain_c8ea3be7-7642-4501-902f-1c77fcd55362_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_02f4a1a8-186e-4a16-acaf-54ac65aa44ad" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_c8ea3be7-7642-4501-902f-1c77fcd55362" xlink:to="loc_srt_OwnershipDomain_02f4a1a8-186e-4a16-acaf-54ac65aa44ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_SandiskCorporationMember_8ce10e3a-7721-4623-bccd-921e6534ebad" xlink:href="sndk-20251003.xsd#sndk_SandiskCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_02f4a1a8-186e-4a16-acaf-54ac65aa44ad" xlink:to="loc_sndk_SandiskCorporationMember_8ce10e3a-7721-4623-bccd-921e6534ebad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_3c1d2cc8-5f34-4532-accc-9d3d5e738b0c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_MinorityInterestTable_1ef88463-0855-4de2-bf2a-2416a748fb48" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_3c1d2cc8-5f34-4532-accc-9d3d5e738b0c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_3c1d2cc8-5f34-4532-accc-9d3d5e738b0c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_3c1d2cc8-5f34-4532-accc-9d3d5e738b0c" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_3c1d2cc8-5f34-4532-accc-9d3d5e738b0c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_e15b887c-2879-4db3-a491-d3f5bb83df34" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_3c1d2cc8-5f34-4532-accc-9d3d5e738b0c" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_e15b887c-2879-4db3-a491-d3f5bb83df34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_SandiskCorporationMember_20cd0633-8b02-40b6-b316-a403d5aace8c" xlink:href="sndk-20251003.xsd#sndk_SandiskCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_e15b887c-2879-4db3-a491-d3f5bb83df34" xlink:to="loc_sndk_SandiskCorporationMember_20cd0633-8b02-40b6-b316-a403d5aace8c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_dd0dda5d-d07a-4233-8377-14d8599567ee" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_MinorityInterestTable_1ef88463-0855-4de2-bf2a-2416a748fb48" xlink:to="loc_us-gaap_CreditFacilityAxis_dd0dda5d-d07a-4233-8377-14d8599567ee" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_dd0dda5d-d07a-4233-8377-14d8599567ee_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_dd0dda5d-d07a-4233-8377-14d8599567ee" xlink:to="loc_us-gaap_CreditFacilityDomain_dd0dda5d-d07a-4233-8377-14d8599567ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_fe07c95c-cb86-41d4-b1f5-7da53140b0c9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_dd0dda5d-d07a-4233-8377-14d8599567ee" xlink:to="loc_us-gaap_CreditFacilityDomain_fe07c95c-cb86-41d4-b1f5-7da53140b0c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_12111e89-ba55-4417-8e26-5b749cb26a8b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_fe07c95c-cb86-41d4-b1f5-7da53140b0c9" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_12111e89-ba55-4417-8e26-5b749cb26a8b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_TermBLoanMember_d33f7dc1-2aea-454a-8629-757c4f8489b8" xlink:href="sndk-20251003.xsd#sndk_TermBLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_fe07c95c-cb86-41d4-b1f5-7da53140b0c9" xlink:to="loc_sndk_TermBLoanMember_d33f7dc1-2aea-454a-8629-757c4f8489b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_e5d199fc-6951-4534-8648-db07d65e852f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_MinorityInterestTable_1ef88463-0855-4de2-bf2a-2416a748fb48" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_e5d199fc-6951-4534-8648-db07d65e852f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_e5d199fc-6951-4534-8648-db07d65e852f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e5d199fc-6951-4534-8648-db07d65e852f" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_e5d199fc-6951-4534-8648-db07d65e852f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3b80d7a3-3c9d-4ee6-80f2-071fd14f7200" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e5d199fc-6951-4534-8648-db07d65e852f" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3b80d7a3-3c9d-4ee6-80f2-071fd14f7200" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_b6721e46-3919-4628-ad6a-2c16f4d1fa0b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3b80d7a3-3c9d-4ee6-80f2-071fd14f7200" xlink:to="loc_us-gaap_LineOfCreditMember_b6721e46-3919-4628-ad6a-2c16f4d1fa0b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_efb98b16-dc47-46fc-8a04-f43312179857" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_MinorityInterestTable_1ef88463-0855-4de2-bf2a-2416a748fb48" xlink:to="loc_srt_CounterpartyNameAxis_efb98b16-dc47-46fc-8a04-f43312179857" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_efb98b16-dc47-46fc-8a04-f43312179857_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_efb98b16-dc47-46fc-8a04-f43312179857" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_efb98b16-dc47-46fc-8a04-f43312179857_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5c3cbf3a-08a1-4b19-a4c8-327d1c0f0878" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_efb98b16-dc47-46fc-8a04-f43312179857" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5c3cbf3a-08a1-4b19-a4c8-327d1c0f0878" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_WesternDigitalCorporationMember_063e4fb0-bbaf-4a00-a661-9651c8f05171" xlink:href="sndk-20251003.xsd#sndk_WesternDigitalCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_5c3cbf3a-08a1-4b19-a4c8-327d1c0f0878" xlink:to="loc_sndk_WesternDigitalCorporationMember_063e4fb0-bbaf-4a00-a661-9651c8f05171" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_SpinOffTransactionProRataDistributionOutstandingShares_46c420d4-cc4c-4ce1-b7e1-c3cc58aa28ca" xlink:href="sndk-20251003.xsd#sndk_SpinOffTransactionProRataDistributionOutstandingShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestLineItems_d38eebf8-63b9-463d-974c-b60efd5b21c3" xlink:to="loc_sndk_SpinOffTransactionProRataDistributionOutstandingShares_46c420d4-cc4c-4ce1-b7e1-c3cc58aa28ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_SpinOffTransactionProRataDistributionOutstandingSharesPercentage_c0967d2e-f268-4cc2-877a-09c057345e55" xlink:href="sndk-20251003.xsd#sndk_SpinOffTransactionProRataDistributionOutstandingSharesPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestLineItems_d38eebf8-63b9-463d-974c-b60efd5b21c3" xlink:to="loc_sndk_SpinOffTransactionProRataDistributionOutstandingSharesPercentage_c0967d2e-f268-4cc2-877a-09c057345e55" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentOwnedBalanceShares_7c3c82af-5b07-4d4f-aec0-57b9186be91b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentOwnedBalanceShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestLineItems_d38eebf8-63b9-463d-974c-b60efd5b21c3" xlink:to="loc_us-gaap_InvestmentOwnedBalanceShares_7c3c82af-5b07-4d4f-aec0-57b9186be91b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_d9711758-7deb-4595-87b8-bc28b6bade2c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestLineItems_d38eebf8-63b9-463d-974c-b60efd5b21c3" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_d9711758-7deb-4595-87b8-bc28b6bade2c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_7ceeb199-1ae0-4568-a0a6-10636b892c16" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestLineItems_d38eebf8-63b9-463d-974c-b60efd5b21c3" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_7ceeb199-1ae0-4568-a0a6-10636b892c16" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividends_2e96043f-6c75-40e0-91f2-edf01923d8ee" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsOfDividends"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestLineItems_d38eebf8-63b9-463d-974c-b60efd5b21c3" xlink:to="loc_us-gaap_PaymentsOfDividends_2e96043f-6c75-40e0-91f2-edf01923d8ee" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_4dc9401d-b331-4011-b01e-eed414b8286d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestLineItems_d38eebf8-63b9-463d-974c-b60efd5b21c3" xlink:to="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_4dc9401d-b331-4011-b01e-eed414b8286d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_DisposalGroupIncludingDiscontinuedOperationsPercentage_9584e63a-a115-4130-acec-6e410e2cce85" xlink:href="sndk-20251003.xsd#sndk_DisposalGroupIncludingDiscontinuedOperationsPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestLineItems_d38eebf8-63b9-463d-974c-b60efd5b21c3" xlink:to="loc_sndk_DisposalGroupIncludingDiscontinuedOperationsPercentage_9584e63a-a115-4130-acec-6e410e2cce85" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_SpinOffTransactionRightToReceivePerShareRatio_d690bf03-8405-421c-abfa-ba59e6a8186b" xlink:href="sndk-20251003.xsd#sndk_SpinOffTransactionRightToReceivePerShareRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestLineItems_d38eebf8-63b9-463d-974c-b60efd5b21c3" xlink:to="loc_sndk_SpinOffTransactionRightToReceivePerShareRatio_d690bf03-8405-421c-abfa-ba59e6a8186b" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/GeographicInformationandConcentrationsofRiskScheduleofDisaggregationofRevenueDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#GeographicInformationandConcentrationsofRiskScheduleofDisaggregationofRevenueDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/GeographicInformationandConcentrationsofRiskScheduleofDisaggregationofRevenueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_cfc27519-1cba-473d-b32a-9574a80a627e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_72e1c93a-3e8f-4730-b905-e24e3a10ef17" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_cfc27519-1cba-473d-b32a-9574a80a627e" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_72e1c93a-3e8f-4730-b905-e24e3a10ef17" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_9a08ac17-0898-40fe-a640-66e37b87e9ef" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_72e1c93a-3e8f-4730-b905-e24e3a10ef17" xlink:to="loc_srt_ProductOrServiceAxis_9a08ac17-0898-40fe-a640-66e37b87e9ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_9a08ac17-0898-40fe-a640-66e37b87e9ef_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_9a08ac17-0898-40fe-a640-66e37b87e9ef" xlink:to="loc_srt_ProductsAndServicesDomain_9a08ac17-0898-40fe-a640-66e37b87e9ef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_287c9c00-eb0f-4c16-9c73-1b0f0bf14fc0" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_9a08ac17-0898-40fe-a640-66e37b87e9ef" xlink:to="loc_srt_ProductsAndServicesDomain_287c9c00-eb0f-4c16-9c73-1b0f0bf14fc0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_DatacenterMember_2d02ed3f-a485-49b3-a6a5-b68b812e87be" xlink:href="sndk-20251003.xsd#sndk_DatacenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_287c9c00-eb0f-4c16-9c73-1b0f0bf14fc0" xlink:to="loc_sndk_DatacenterMember_2d02ed3f-a485-49b3-a6a5-b68b812e87be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_EdgeMember_71601f5d-0284-4fb9-b4e5-366f31379a7e" xlink:href="sndk-20251003.xsd#sndk_EdgeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_287c9c00-eb0f-4c16-9c73-1b0f0bf14fc0" xlink:to="loc_sndk_EdgeMember_71601f5d-0284-4fb9-b4e5-366f31379a7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_ConsumerMember_b2e90c1e-94f2-4926-836b-e6fd6323311c" xlink:href="sndk-20251003.xsd#sndk_ConsumerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_287c9c00-eb0f-4c16-9c73-1b0f0bf14fc0" xlink:to="loc_sndk_ConsumerMember_b2e90c1e-94f2-4926-836b-e6fd6323311c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_b5df811f-356c-4b43-97bc-aba7abe4933c" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_72e1c93a-3e8f-4730-b905-e24e3a10ef17" xlink:to="loc_srt_StatementGeographicalAxis_b5df811f-356c-4b43-97bc-aba7abe4933c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_b5df811f-356c-4b43-97bc-aba7abe4933c_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_b5df811f-356c-4b43-97bc-aba7abe4933c" xlink:to="loc_srt_SegmentGeographicalDomain_b5df811f-356c-4b43-97bc-aba7abe4933c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_bd277418-58c5-44e8-b8ab-2a3d4d1785b8" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_b5df811f-356c-4b43-97bc-aba7abe4933c" xlink:to="loc_srt_SegmentGeographicalDomain_bd277418-58c5-44e8-b8ab-2a3d4d1785b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaMember_388137cf-a4f7-499e-878b-fa649b408944" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_AsiaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bd277418-58c5-44e8-b8ab-2a3d4d1785b8" xlink:to="loc_srt_AsiaMember_388137cf-a4f7-499e-878b-fa649b408944" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AmericasMember_ef73e69a-5890-4684-97df-c1e464984af6" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_AmericasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bd277418-58c5-44e8-b8ab-2a3d4d1785b8" xlink:to="loc_srt_AmericasMember_ef73e69a-5890-4684-97df-c1e464984af6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EMEAMember_eeca9a99-5692-40f2-ab4e-b4b9db26d8d8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EMEAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bd277418-58c5-44e8-b8ab-2a3d4d1785b8" xlink:to="loc_us-gaap_EMEAMember_eeca9a99-5692-40f2-ab4e-b4b9db26d8d8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_c7d056bb-c4c4-45e3-a672-92b5f5f809e7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_cfc27519-1cba-473d-b32a-9574a80a627e" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_c7d056bb-c4c4-45e3-a672-92b5f5f809e7" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/GeographicInformationandConcentrationsofRiskAdditionalInformationDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#GeographicInformationandConcentrationsofRiskAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/GeographicInformationandConcentrationsofRiskAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_2e91a1ad-f2ef-49cd-9fef-456bdea69475" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_c1264c8d-050f-4807-b2f0-b81710ae8d66" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_2e91a1ad-f2ef-49cd-9fef-456bdea69475" xlink:to="loc_us-gaap_ConcentrationRiskTable_c1264c8d-050f-4807-b2f0-b81710ae8d66" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_358ebe00-cf9c-49fa-8691-5cfe7478f63d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_c1264c8d-050f-4807-b2f0-b81710ae8d66" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_358ebe00-cf9c-49fa-8691-5cfe7478f63d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_358ebe00-cf9c-49fa-8691-5cfe7478f63d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_358ebe00-cf9c-49fa-8691-5cfe7478f63d" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_358ebe00-cf9c-49fa-8691-5cfe7478f63d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_2453e1a1-f3b5-4f37-a8ec-4e11edd45918" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_358ebe00-cf9c-49fa-8691-5cfe7478f63d" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_2453e1a1-f3b5-4f37-a8ec-4e11edd45918" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerMember_9fc57879-81b9-4a61-9fe7-2c3023280162" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_2453e1a1-f3b5-4f37-a8ec-4e11edd45918" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerMember_9fc57879-81b9-4a61-9fe7-2c3023280162" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_69e07a26-0656-44ed-9d07-015ea93fa0f5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_c1264c8d-050f-4807-b2f0-b81710ae8d66" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_69e07a26-0656-44ed-9d07-015ea93fa0f5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_69e07a26-0656-44ed-9d07-015ea93fa0f5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_69e07a26-0656-44ed-9d07-015ea93fa0f5" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_69e07a26-0656-44ed-9d07-015ea93fa0f5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_825ceb8a-c53d-4413-a68e-cbeef753f9a4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_69e07a26-0656-44ed-9d07-015ea93fa0f5" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_825ceb8a-c53d-4413-a68e-cbeef753f9a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_b8e71627-622e-47c0-8909-9e6c1cc05932" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_825ceb8a-c53d-4413-a68e-cbeef753f9a4" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_b8e71627-622e-47c0-8909-9e6c1cc05932" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_2ff083bc-673c-4da2-8724-d9c6805fc1e4" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_c1264c8d-050f-4807-b2f0-b81710ae8d66" xlink:to="loc_srt_MajorCustomersAxis_2ff083bc-673c-4da2-8724-d9c6805fc1e4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_2ff083bc-673c-4da2-8724-d9c6805fc1e4_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_2ff083bc-673c-4da2-8724-d9c6805fc1e4" xlink:to="loc_srt_NameOfMajorCustomerDomain_2ff083bc-673c-4da2-8724-d9c6805fc1e4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_6526fbce-438b-4864-9abf-df3b9cfcd39b" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_2ff083bc-673c-4da2-8724-d9c6805fc1e4" xlink:to="loc_srt_NameOfMajorCustomerDomain_6526fbce-438b-4864-9abf-df3b9cfcd39b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_TopTenCustomersMember_78d4fd1f-96e4-42af-bdda-6ed41380c74f" xlink:href="sndk-20251003.xsd#sndk_TopTenCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_6526fbce-438b-4864-9abf-df3b9cfcd39b" xlink:to="loc_sndk_TopTenCustomersMember_78d4fd1f-96e4-42af-bdda-6ed41380c74f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_19dee260-e514-445b-a848-6ad0c3e5687b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_2e91a1ad-f2ef-49cd-9fef-456bdea69475" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_19dee260-e514-445b-a848-6ad0c3e5687b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/SupplementalFinancialStatementDataDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#SupplementalFinancialStatementDataDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/SupplementalFinancialStatementDataDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_0b3bc1e9-5fae-49ee-b136-bb3fef8eceed" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_37824bd7-b752-4584-8862-63ce2a258de1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0b3bc1e9-5fae-49ee-b136-bb3fef8eceed" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_37824bd7-b752-4584-8862-63ce2a258de1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_7ceb0995-fc42-4400-aef7-5a6d16c01dd6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_37824bd7-b752-4584-8862-63ce2a258de1" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_7ceb0995-fc42-4400-aef7-5a6d16c01dd6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_7ceb0995-fc42-4400-aef7-5a6d16c01dd6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_7ceb0995-fc42-4400-aef7-5a6d16c01dd6" xlink:to="loc_us-gaap_RelatedPartyDomain_7ceb0995-fc42-4400-aef7-5a6d16c01dd6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_ff70ad44-2da0-45b4-9c3e-58b634adb208" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_7ceb0995-fc42-4400-aef7-5a6d16c01dd6" xlink:to="loc_us-gaap_RelatedPartyDomain_ff70ad44-2da0-45b4-9c3e-58b634adb208" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_a1e9b8dd-5c77-430f-9172-f9b9767d66a5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_ff70ad44-2da0-45b4-9c3e-58b634adb208" xlink:to="loc_us-gaap_RelatedPartyMember_a1e9b8dd-5c77-430f-9172-f9b9767d66a5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_01a251dc-31e7-46a8-9005-bd984f963fc3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0b3bc1e9-5fae-49ee-b136-bb3fef8eceed" xlink:to="loc_us-gaap_NumberOfOperatingSegments_01a251dc-31e7-46a8-9005-bd984f963fc3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_600ec87b-8b88-4b6c-938c-257eaf4009d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0b3bc1e9-5fae-49ee-b136-bb3fef8eceed" xlink:to="loc_us-gaap_NumberOfReportableSegments_600ec87b-8b88-4b6c-938c-257eaf4009d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportingUnits_d834635a-430e-4cea-a582-e4d7906fd3c9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfReportingUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0b3bc1e9-5fae-49ee-b136-bb3fef8eceed" xlink:to="loc_us-gaap_NumberOfReportingUnits_d834635a-430e-4cea-a582-e4d7906fd3c9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_TaxLiabilityIndemnification_79707956-d9db-42c0-b0ca-5e4177ae8c10" xlink:href="sndk-20251003.xsd#sndk_TaxLiabilityIndemnification"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_0b3bc1e9-5fae-49ee-b136-bb3fef8eceed" xlink:to="loc_sndk_TaxLiabilityIndemnification_79707956-d9db-42c0-b0ca-5e4177ae8c10" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/SupplementalFinancialStatementDataAccountsReceivableNetDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#SupplementalFinancialStatementDataAccountsReceivableNetDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/SupplementalFinancialStatementDataAccountsReceivableNetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_095eacef-6dc1-41ff-9e73-7ee8a3d9d1d1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_0525c1a4-ea32-4b91-91e2-84a6be0cd848" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_095eacef-6dc1-41ff-9e73-7ee8a3d9d1d1" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_0525c1a4-ea32-4b91-91e2-84a6be0cd848" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_faa9f07e-72e7-4faa-a8a3-4995bbcd8e90" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_0525c1a4-ea32-4b91-91e2-84a6be0cd848" xlink:to="loc_dei_LegalEntityAxis_faa9f07e-72e7-4faa-a8a3-4995bbcd8e90" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_faa9f07e-72e7-4faa-a8a3-4995bbcd8e90_default" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_faa9f07e-72e7-4faa-a8a3-4995bbcd8e90" xlink:to="loc_dei_EntityDomain_faa9f07e-72e7-4faa-a8a3-4995bbcd8e90_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_106d8351-8dff-4f6d-87d3-9b4c17964644" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_faa9f07e-72e7-4faa-a8a3-4995bbcd8e90" xlink:to="loc_dei_EntityDomain_106d8351-8dff-4f6d-87d3-9b4c17964644" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_WesternDigitalCorporationMember_6854164c-b989-4549-9b66-84f3707daa1d" xlink:href="sndk-20251003.xsd#sndk_WesternDigitalCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_106d8351-8dff-4f6d-87d3-9b4c17964644" xlink:to="loc_sndk_WesternDigitalCorporationMember_6854164c-b989-4549-9b66-84f3707daa1d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleAndCollectionOfReceivables_f23e555d-3354-45f7-8b17-70d99b9f2619" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromSaleAndCollectionOfReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_095eacef-6dc1-41ff-9e73-7ee8a3d9d1d1" xlink:to="loc_us-gaap_ProceedsFromSaleAndCollectionOfReceivables_f23e555d-3354-45f7-8b17-70d99b9f2619" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_AccountsReceivablesFactored_874ebb0f-3756-4495-bd80-daea1c7acfb3" xlink:href="sndk-20251003.xsd#sndk_AccountsReceivablesFactored"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_095eacef-6dc1-41ff-9e73-7ee8a3d9d1d1" xlink:to="loc_sndk_AccountsReceivablesFactored_874ebb0f-3756-4495-bd80-daea1c7acfb3" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/SupplementalFinancialStatementDataScheduleofPropertyPlantandEquipmentNetDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#SupplementalFinancialStatementDataScheduleofPropertyPlantandEquipmentNetDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/SupplementalFinancialStatementDataScheduleofPropertyPlantandEquipmentNetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_4dba255f-7e47-44ee-80ae-2ab0f1213364" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_81f6869d-a323-4838-af47-554c863b68d8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_4dba255f-7e47-44ee-80ae-2ab0f1213364" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_81f6869d-a323-4838-af47-554c863b68d8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_b425111b-2e3f-4aa3-93b7-c57cca5ae9a9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_81f6869d-a323-4838-af47-554c863b68d8" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_b425111b-2e3f-4aa3-93b7-c57cca5ae9a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_b425111b-2e3f-4aa3-93b7-c57cca5ae9a9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_b425111b-2e3f-4aa3-93b7-c57cca5ae9a9" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_b425111b-2e3f-4aa3-93b7-c57cca5ae9a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6b88f72d-7de0-44d6-92f8-5da571fe6e9e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_b425111b-2e3f-4aa3-93b7-c57cca5ae9a9" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6b88f72d-7de0-44d6-92f8-5da571fe6e9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_81f2b190-11a8-414c-8765-f4be63429c17" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6b88f72d-7de0-44d6-92f8-5da571fe6e9e" xlink:to="loc_us-gaap_LandMember_81f2b190-11a8-414c-8765-f4be63429c17" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_c0953295-601c-40e2-a88e-18b6b642d61b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MachineryAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6b88f72d-7de0-44d6-92f8-5da571fe6e9e" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_c0953295-601c-40e2-a88e-18b6b642d61b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_71737233-2ff0-4bf1-9884-1d2aed03e7d5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6b88f72d-7de0-44d6-92f8-5da571fe6e9e" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_71737233-2ff0-4bf1-9884-1d2aed03e7d5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_ComputerEquipmentandSoftwareMember_0a6712f2-394a-43a5-9d55-986d67c5c80c" xlink:href="sndk-20251003.xsd#sndk_ComputerEquipmentandSoftwareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6b88f72d-7de0-44d6-92f8-5da571fe6e9e" xlink:to="loc_sndk_ComputerEquipmentandSoftwareMember_0a6712f2-394a-43a5-9d55-986d67c5c80c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_76d0870b-9975-450e-8388-3cdc65881e45" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6b88f72d-7de0-44d6-92f8-5da571fe6e9e" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_76d0870b-9975-450e-8388-3cdc65881e45" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_e472a567-fa6c-4dba-a801-de7597dda114" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6b88f72d-7de0-44d6-92f8-5da571fe6e9e" xlink:to="loc_us-gaap_ConstructionInProgressMember_e472a567-fa6c-4dba-a801-de7597dda114" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_eaae46d4-33d5-47d8-9e9a-9d346ee3edf8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_4dba255f-7e47-44ee-80ae-2ab0f1213364" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_eaae46d4-33d5-47d8-9e9a-9d346ee3edf8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_f2605dd4-e31d-4a7b-8392-852ecb34a2a5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_4dba255f-7e47-44ee-80ae-2ab0f1213364" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_f2605dd4-e31d-4a7b-8392-852ecb34a2a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_da3b1843-de97-46eb-b4bb-b9bff5de7d5e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_4dba255f-7e47-44ee-80ae-2ab0f1213364" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_da3b1843-de97-46eb-b4bb-b9bff5de7d5e" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/SupplementalFinancialStatementDataScheduleofAccumulatedOtherComprehensiveLossDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#SupplementalFinancialStatementDataScheduleofAccumulatedOtherComprehensiveLossDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/SupplementalFinancialStatementDataScheduleofAccumulatedOtherComprehensiveLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_ea8b11e9-4be5-4f77-ac0b-455758e94a4a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_2de2800b-bf20-496b-829e-5edd13f7f835" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_ea8b11e9-4be5-4f77-ac0b-455758e94a4a" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_2de2800b-bf20-496b-829e-5edd13f7f835" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_8f057016-b6e9-47cb-94df-a5c318861efe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_2de2800b-bf20-496b-829e-5edd13f7f835" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_8f057016-b6e9-47cb-94df-a5c318861efe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_8f057016-b6e9-47cb-94df-a5c318861efe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_8f057016-b6e9-47cb-94df-a5c318861efe" xlink:to="loc_us-gaap_EquityComponentDomain_8f057016-b6e9-47cb-94df-a5c318861efe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_b22a34d9-f709-4ebc-b9ad-ebb5fcfe8dd7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_8f057016-b6e9-47cb-94df-a5c318861efe" xlink:to="loc_us-gaap_EquityComponentDomain_b22a34d9-f709-4ebc-b9ad-ebb5fcfe8dd7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_aad79ae5-6ad3-4fe1-919a-a3e9fcf7773c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_b22a34d9-f709-4ebc-b9ad-ebb5fcfe8dd7" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_aad79ae5-6ad3-4fe1-919a-a3e9fcf7773c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_b5126bd0-9fd9-42a6-8691-4d93f6124162" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_aad79ae5-6ad3-4fe1-919a-a3e9fcf7773c" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_b5126bd0-9fd9-42a6-8691-4d93f6124162" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_455e335d-c706-4bd5-9882-a2984b5e66ac" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_aad79ae5-6ad3-4fe1-919a-a3e9fcf7773c" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_455e335d-c706-4bd5-9882-a2984b5e66ac" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_7f54691b-b1b9-4368-bc6d-138fe59e2231" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_ea8b11e9-4be5-4f77-ac0b-455758e94a4a" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_7f54691b-b1b9-4368-bc6d-138fe59e2231" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_5c856cce-39b5-41d1-a63d-e030a40dbe58" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_7f54691b-b1b9-4368-bc6d-138fe59e2231" xlink:to="loc_us-gaap_StockholdersEquity_5c856cce-39b5-41d1-a63d-e030a40dbe58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent_1562b409-6693-4bfe-aaee-55ad15726386" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_7f54691b-b1b9-4368-bc6d-138fe59e2231" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent_1562b409-6693-4bfe-aaee-55ad15726386" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_5ae8b4dc-752e-4c21-8435-8186ec3cdc9c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_7f54691b-b1b9-4368-bc6d-138fe59e2231" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_5ae8b4dc-752e-4c21-8435-8186ec3cdc9c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_f0d3224d-f5a3-497f-b183-ee171e010a02" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_7f54691b-b1b9-4368-bc6d-138fe59e2231" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_f0d3224d-f5a3-497f-b183-ee171e010a02" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_d82ade8a-1892-441b-9e5c-d33edfb74c29" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/FairValueMeasurementsandInvestmentsScheduleofFinancialAssetsandLiabilitiesMeasuredatFairValueonRecurringBasisDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#FairValueMeasurementsandInvestmentsScheduleofFinancialAssetsandLiabilitiesMeasuredatFairValueonRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/FairValueMeasurementsandInvestmentsScheduleofFinancialAssetsandLiabilitiesMeasuredatFairValueonRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_62214553-bdcf-4921-87cf-aa7939afb77c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_99a32815-ddc8-4fd2-b3c5-1885ed6e3951" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_62214553-bdcf-4921-87cf-aa7939afb77c" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_99a32815-ddc8-4fd2-b3c5-1885ed6e3951" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_c04803cd-b57f-42c1-b727-dc48066e48a6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_99a32815-ddc8-4fd2-b3c5-1885ed6e3951" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_c04803cd-b57f-42c1-b727-dc48066e48a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_c04803cd-b57f-42c1-b727-dc48066e48a6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_c04803cd-b57f-42c1-b727-dc48066e48a6" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_c04803cd-b57f-42c1-b727-dc48066e48a6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_8909820d-e0e1-4b7e-9f28-7bf69bcb0121" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_c04803cd-b57f-42c1-b727-dc48066e48a6" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_8909820d-e0e1-4b7e-9f28-7bf69bcb0121" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_c1444aa4-40a0-4db0-9e10-e1e12a59126d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_8909820d-e0e1-4b7e-9f28-7bf69bcb0121" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_c1444aa4-40a0-4db0-9e10-e1e12a59126d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_9d58681c-1fc2-4df4-9467-41420133d4a4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_99a32815-ddc8-4fd2-b3c5-1885ed6e3951" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_9d58681c-1fc2-4df4-9467-41420133d4a4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9d58681c-1fc2-4df4-9467-41420133d4a4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_9d58681c-1fc2-4df4-9467-41420133d4a4" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_9d58681c-1fc2-4df4-9467-41420133d4a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_df8aee2a-161c-45a8-aa70-78451035d676" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_9d58681c-1fc2-4df4-9467-41420133d4a4" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_df8aee2a-161c-45a8-aa70-78451035d676" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_88a26b05-eafb-4088-afca-b40bbb392c95" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_df8aee2a-161c-45a8-aa70-78451035d676" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_88a26b05-eafb-4088-afca-b40bbb392c95" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_bec15f0a-c265-40b8-8897-5ede393eb514" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_df8aee2a-161c-45a8-aa70-78451035d676" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_bec15f0a-c265-40b8-8897-5ede393eb514" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_9f65a622-aac4-45e2-a684-0ecd78465ff8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_df8aee2a-161c-45a8-aa70-78451035d676" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_9f65a622-aac4-45e2-a684-0ecd78465ff8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_1c2ba695-ebb2-4798-bae6-774d8ae03ed3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_99a32815-ddc8-4fd2-b3c5-1885ed6e3951" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_1c2ba695-ebb2-4798-bae6-774d8ae03ed3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_1c2ba695-ebb2-4798-bae6-774d8ae03ed3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_1c2ba695-ebb2-4798-bae6-774d8ae03ed3" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_1c2ba695-ebb2-4798-bae6-774d8ae03ed3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_66d6c90a-bd3a-4a2d-84f4-82e3d32bbe75" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_1c2ba695-ebb2-4798-bae6-774d8ae03ed3" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_66d6c90a-bd3a-4a2d-84f4-82e3d32bbe75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_807ad043-da62-4a82-acbd-4d837493a809" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_66d6c90a-bd3a-4a2d-84f4-82e3d32bbe75" xlink:to="loc_us-gaap_MoneyMarketFundsMember_807ad043-da62-4a82-acbd-4d837493a809" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_b3325bd1-ec50-4218-92af-ddb30e33a4e3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_99a32815-ddc8-4fd2-b3c5-1885ed6e3951" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_b3325bd1-ec50-4218-92af-ddb30e33a4e3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_b3325bd1-ec50-4218-92af-ddb30e33a4e3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_b3325bd1-ec50-4218-92af-ddb30e33a4e3" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_b3325bd1-ec50-4218-92af-ddb30e33a4e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_f8ae8c7d-fd91-4b68-8b03-a2197c7739b4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_b3325bd1-ec50-4218-92af-ddb30e33a4e3" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_f8ae8c7d-fd91-4b68-8b03-a2197c7739b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_b3bac77d-7725-4555-b1fd-e840173b0db2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_f8ae8c7d-fd91-4b68-8b03-a2197c7739b4" xlink:to="loc_us-gaap_ForeignExchangeContractMember_b3bac77d-7725-4555-b1fd-e840173b0db2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_31295806-b3a8-49b0-b93c-b1d6176fd644" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_62214553-bdcf-4921-87cf-aa7939afb77c" xlink:to="loc_us-gaap_AssetsAbstract_31295806-b3a8-49b0-b93c-b1d6176fd644" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_7512ae34-4993-4cd2-bf0b-94e4168870ab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_31295806-b3a8-49b0-b93c-b1d6176fd644" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_7512ae34-4993-4cd2-bf0b-94e4168870ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_b00943fd-90b4-4ab9-991e-abddfd4a97a6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_31295806-b3a8-49b0-b93c-b1d6176fd644" xlink:to="loc_us-gaap_DerivativeAssets_b00943fd-90b4-4ab9-991e-abddfd4a97a6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_30422da4-076a-48bf-b7b9-b921aaebc50b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_31295806-b3a8-49b0-b93c-b1d6176fd644" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_30422da4-076a-48bf-b7b9-b921aaebc50b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_e090bfe7-f1c5-45d9-8554-9b98d74233d8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_62214553-bdcf-4921-87cf-aa7939afb77c" xlink:to="loc_us-gaap_LiabilitiesAbstract_e090bfe7-f1c5-45d9-8554-9b98d74233d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_4914b93e-2faf-47f3-958e-56f0dcdaee4d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_e090bfe7-f1c5-45d9-8554-9b98d74233d8" xlink:to="loc_us-gaap_DerivativeLiabilities_4914b93e-2faf-47f3-958e-56f0dcdaee4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_0b4dbf81-08d0-41d4-a3b3-a2e0a181b9ee" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_e090bfe7-f1c5-45d9-8554-9b98d74233d8" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_0b4dbf81-08d0-41d4-a3b3-a2e0a181b9ee" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFairValue_eb3bd7f8-67ad-466b-a744-7e85d204e941" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_62214553-bdcf-4921-87cf-aa7939afb77c" xlink:to="loc_us-gaap_DebtInstrumentFairValue_eb3bd7f8-67ad-466b-a744-7e85d204e941" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/DerivativeInstrumentsandHedgingActivitiesDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#DerivativeInstrumentsandHedgingActivitiesDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/DerivativeInstrumentsandHedgingActivitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_158786b6-2f7d-486c-a425-5f37b7a353ea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_931235d1-927e-483e-ab45-99808c179da1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_158786b6-2f7d-486c-a425-5f37b7a353ea" xlink:to="loc_us-gaap_DerivativeTable_931235d1-927e-483e-ab45-99808c179da1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_3a0d5216-1821-4496-8a30-d55068dba4e7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_931235d1-927e-483e-ab45-99808c179da1" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_3a0d5216-1821-4496-8a30-d55068dba4e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_3a0d5216-1821-4496-8a30-d55068dba4e7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_3a0d5216-1821-4496-8a30-d55068dba4e7" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_3a0d5216-1821-4496-8a30-d55068dba4e7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_97d42f06-ee65-4d93-a9da-58c880c23271" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_3a0d5216-1821-4496-8a30-d55068dba4e7" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_97d42f06-ee65-4d93-a9da-58c880c23271" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_8fe5a121-6dc0-4830-9217-a297f69b322c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_97d42f06-ee65-4d93-a9da-58c880c23271" xlink:to="loc_us-gaap_ForeignExchangeContractMember_8fe5a121-6dc0-4830-9217-a297f69b322c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_35249055-dd8c-4bcd-bfb1-66792891e61a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnDerivativeInstrumentsNetPretax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_158786b6-2f7d-486c-a425-5f37b7a353ea" xlink:to="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_35249055-dd8c-4bcd-bfb1-66792891e61a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/DebtScheduleofDebtDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#DebtScheduleofDebtDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/DebtScheduleofDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_93dc82dd-3b4d-4bc1-a49e-ec05b2d6df05" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_a94e81a6-3dc0-49b0-8a70-3992119e6f31" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_93dc82dd-3b4d-4bc1-a49e-ec05b2d6df05" xlink:to="loc_us-gaap_DebtInstrumentTable_a94e81a6-3dc0-49b0-8a70-3992119e6f31" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_b5689c1b-9dbf-4422-9947-43d3a2a94397" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a94e81a6-3dc0-49b0-8a70-3992119e6f31" xlink:to="loc_us-gaap_CreditFacilityAxis_b5689c1b-9dbf-4422-9947-43d3a2a94397" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_b5689c1b-9dbf-4422-9947-43d3a2a94397_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_b5689c1b-9dbf-4422-9947-43d3a2a94397" xlink:to="loc_us-gaap_CreditFacilityDomain_b5689c1b-9dbf-4422-9947-43d3a2a94397_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_c0d4cdf8-325f-4cd1-af61-7c9e1e0feda1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_b5689c1b-9dbf-4422-9947-43d3a2a94397" xlink:to="loc_us-gaap_CreditFacilityDomain_c0d4cdf8-325f-4cd1-af61-7c9e1e0feda1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_TermBLoanMember_145d09d5-df6c-4788-a5fd-f096ff8fde34" xlink:href="sndk-20251003.xsd#sndk_TermBLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_c0d4cdf8-325f-4cd1-af61-7c9e1e0feda1" xlink:to="loc_sndk_TermBLoanMember_145d09d5-df6c-4788-a5fd-f096ff8fde34" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_db0bc910-1921-43e3-8111-d42d1be897db" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_c0d4cdf8-325f-4cd1-af61-7c9e1e0feda1" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_db0bc910-1921-43e3-8111-d42d1be897db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_55ad59a3-ba69-462b-935b-b5da6ec51d6d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a94e81a6-3dc0-49b0-8a70-3992119e6f31" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_55ad59a3-ba69-462b-935b-b5da6ec51d6d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_55ad59a3-ba69-462b-935b-b5da6ec51d6d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_55ad59a3-ba69-462b-935b-b5da6ec51d6d" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_55ad59a3-ba69-462b-935b-b5da6ec51d6d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_c0337090-bfa1-42ff-ad45-bec46b7fee9e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_55ad59a3-ba69-462b-935b-b5da6ec51d6d" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_c0337090-bfa1-42ff-ad45-bec46b7fee9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_a939fbc0-e8cf-4c4d-89c1-0a17dc490cdd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_c0337090-bfa1-42ff-ad45-bec46b7fee9e" xlink:to="loc_us-gaap_LineOfCreditMember_a939fbc0-e8cf-4c4d-89c1-0a17dc490cdd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_a3b40a1c-e885-4691-a592-bbfdde87c2df" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_93dc82dd-3b4d-4bc1-a49e-ec05b2d6df05" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_a3b40a1c-e885-4691-a592-bbfdde87c2df" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_7e6084fc-c025-4cba-a55a-21fef37c6e05" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_93dc82dd-3b4d-4bc1-a49e-ec05b2d6df05" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_7e6084fc-c025-4cba-a55a-21fef37c6e05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_25c9c4ca-e05c-4ebc-afec-e15fe539aee9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_93dc82dd-3b4d-4bc1-a49e-ec05b2d6df05" xlink:to="loc_us-gaap_LongTermDebt_25c9c4ca-e05c-4ebc-afec-e15fe539aee9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_b519d619-c3fe-455a-b76c-751ce574c56b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_93dc82dd-3b4d-4bc1-a49e-ec05b2d6df05" xlink:to="loc_us-gaap_LongTermDebtCurrent_b519d619-c3fe-455a-b76c-751ce574c56b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_19c372f0-9d41-4048-9233-ec59052014b5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_93dc82dd-3b4d-4bc1-a49e-ec05b2d6df05" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_19c372f0-9d41-4048-9233-ec59052014b5" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/DebtAdditionalInformationDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#DebtAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/DebtAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_a0569672-cbda-46c6-95a6-9c8c20fd3174" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_d1a353a6-b4c0-4433-81eb-50fc7859ae96" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a0569672-cbda-46c6-95a6-9c8c20fd3174" xlink:to="loc_us-gaap_DebtInstrumentTable_d1a353a6-b4c0-4433-81eb-50fc7859ae96" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_ff55b2db-1a59-4b68-b866-50e45f908518" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d1a353a6-b4c0-4433-81eb-50fc7859ae96" xlink:to="loc_us-gaap_CreditFacilityAxis_ff55b2db-1a59-4b68-b866-50e45f908518" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_ff55b2db-1a59-4b68-b866-50e45f908518_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_ff55b2db-1a59-4b68-b866-50e45f908518" xlink:to="loc_us-gaap_CreditFacilityDomain_ff55b2db-1a59-4b68-b866-50e45f908518_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_5a9c2783-c082-4519-9cac-66b712435839" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_ff55b2db-1a59-4b68-b866-50e45f908518" xlink:to="loc_us-gaap_CreditFacilityDomain_5a9c2783-c082-4519-9cac-66b712435839" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_57f5706b-aece-4448-960e-32d0ecc3891a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_5a9c2783-c082-4519-9cac-66b712435839" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_57f5706b-aece-4448-960e-32d0ecc3891a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_88e68f0f-111e-43b6-b5a4-39bc7da6f26b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d1a353a6-b4c0-4433-81eb-50fc7859ae96" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_88e68f0f-111e-43b6-b5a4-39bc7da6f26b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_88e68f0f-111e-43b6-b5a4-39bc7da6f26b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_88e68f0f-111e-43b6-b5a4-39bc7da6f26b" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_88e68f0f-111e-43b6-b5a4-39bc7da6f26b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_2d21e0dc-633b-482d-b8eb-da9baea19d3e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_88e68f0f-111e-43b6-b5a4-39bc7da6f26b" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_2d21e0dc-633b-482d-b8eb-da9baea19d3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_b7a4aac1-a336-432a-a920-1f6bf2a5d4ee" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_2d21e0dc-633b-482d-b8eb-da9baea19d3e" xlink:to="loc_us-gaap_LineOfCreditMember_b7a4aac1-a336-432a-a920-1f6bf2a5d4ee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_a01712b2-0ea2-47ef-b672-6e7a62d8e33f" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d1a353a6-b4c0-4433-81eb-50fc7859ae96" xlink:to="loc_srt_CounterpartyNameAxis_a01712b2-0ea2-47ef-b672-6e7a62d8e33f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_a01712b2-0ea2-47ef-b672-6e7a62d8e33f_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_a01712b2-0ea2-47ef-b672-6e7a62d8e33f" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_a01712b2-0ea2-47ef-b672-6e7a62d8e33f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f44069a6-69af-4850-9a05-564a19af169e" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_a01712b2-0ea2-47ef-b672-6e7a62d8e33f" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f44069a6-69af-4850-9a05-564a19af169e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_WesternDigitalCorporationMember_1778ddd1-e10c-4673-b2af-8a53af384e79" xlink:href="sndk-20251003.xsd#sndk_WesternDigitalCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f44069a6-69af-4850-9a05-564a19af169e" xlink:to="loc_sndk_WesternDigitalCorporationMember_1778ddd1-e10c-4673-b2af-8a53af384e79" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_34c1d306-66ff-42d1-98c8-af85a40e4b8d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a0569672-cbda-46c6-95a6-9c8c20fd3174" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_34c1d306-66ff-42d1-98c8-af85a40e4b8d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividends_719a326c-6442-4b8b-8f9c-66d943dcde37" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsOfDividends"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a0569672-cbda-46c6-95a6-9c8c20fd3174" xlink:to="loc_us-gaap_PaymentsOfDividends_719a326c-6442-4b8b-8f9c-66d943dcde37" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/DebtTermLoanFacilityDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#DebtTermLoanFacilityDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/DebtTermLoanFacilityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_df039359-ef1f-43d1-9d71-4d5b8b2e38e8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_1d94b40f-dc01-4aa9-b6f9-d239e918c470" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_df039359-ef1f-43d1-9d71-4d5b8b2e38e8" xlink:to="loc_us-gaap_DebtInstrumentTable_1d94b40f-dc01-4aa9-b6f9-d239e918c470" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_7fe96ac4-9eed-49bf-989e-fbb3c7e2b8d1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1d94b40f-dc01-4aa9-b6f9-d239e918c470" xlink:to="loc_us-gaap_CreditFacilityAxis_7fe96ac4-9eed-49bf-989e-fbb3c7e2b8d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_7fe96ac4-9eed-49bf-989e-fbb3c7e2b8d1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_7fe96ac4-9eed-49bf-989e-fbb3c7e2b8d1" xlink:to="loc_us-gaap_CreditFacilityDomain_7fe96ac4-9eed-49bf-989e-fbb3c7e2b8d1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_1417dca1-e66b-4cb3-b289-60fed42b66da" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_7fe96ac4-9eed-49bf-989e-fbb3c7e2b8d1" xlink:to="loc_us-gaap_CreditFacilityDomain_1417dca1-e66b-4cb3-b289-60fed42b66da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_TermBLoanMember_4aeb7fc0-6ab6-4547-9758-1bef39b718c3" xlink:href="sndk-20251003.xsd#sndk_TermBLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_1417dca1-e66b-4cb3-b289-60fed42b66da" xlink:to="loc_sndk_TermBLoanMember_4aeb7fc0-6ab6-4547-9758-1bef39b718c3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_f17a3854-119a-47c1-ad98-f22b68dd71b0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1d94b40f-dc01-4aa9-b6f9-d239e918c470" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_f17a3854-119a-47c1-ad98-f22b68dd71b0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_f17a3854-119a-47c1-ad98-f22b68dd71b0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_f17a3854-119a-47c1-ad98-f22b68dd71b0" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_f17a3854-119a-47c1-ad98-f22b68dd71b0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_864da9c3-6c9f-4738-b706-549654442cec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_f17a3854-119a-47c1-ad98-f22b68dd71b0" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_864da9c3-6c9f-4738-b706-549654442cec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_c37885bb-70a2-4ee2-9e69-2f27d9115723" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_864da9c3-6c9f-4738-b706-549654442cec" xlink:to="loc_us-gaap_LineOfCreditMember_c37885bb-70a2-4ee2-9e69-2f27d9115723" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_1ef2f55d-2033-4500-a424-e8b1666e2ee8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1d94b40f-dc01-4aa9-b6f9-d239e918c470" xlink:to="loc_us-gaap_VariableRateAxis_1ef2f55d-2033-4500-a424-e8b1666e2ee8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_1ef2f55d-2033-4500-a424-e8b1666e2ee8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_1ef2f55d-2033-4500-a424-e8b1666e2ee8" xlink:to="loc_us-gaap_VariableRateDomain_1ef2f55d-2033-4500-a424-e8b1666e2ee8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_ffb412f4-3997-453e-bdc6-7ea4b3aa327a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_1ef2f55d-2033-4500-a424-e8b1666e2ee8" xlink:to="loc_us-gaap_VariableRateDomain_ffb412f4-3997-453e-bdc6-7ea4b3aa327a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_45f74e80-6326-4255-a9ca-2d0b1f28e27c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_ffb412f4-3997-453e-bdc6-7ea4b3aa327a" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_45f74e80-6326-4255-a9ca-2d0b1f28e27c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_09a9a441-29b3-4e4a-b9c0-d26a7d442d03" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_ffb412f4-3997-453e-bdc6-7ea4b3aa327a" xlink:to="loc_us-gaap_BaseRateMember_09a9a441-29b3-4e4a-b9c0-d26a7d442d03" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_ae3a7fb8-baf3-4315-84b9-29c2a75995ba" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_df039359-ef1f-43d1-9d71-4d5b8b2e38e8" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_ae3a7fb8-baf3-4315-84b9-29c2a75995ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_DebtInstrumentPeriodicPaymentPercentageOfPrincipal_37d1e126-bda0-4d33-9787-35e8548166e7" xlink:href="sndk-20251003.xsd#sndk_DebtInstrumentPeriodicPaymentPercentageOfPrincipal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_df039359-ef1f-43d1-9d71-4d5b8b2e38e8" xlink:to="loc_sndk_DebtInstrumentPeriodicPaymentPercentageOfPrincipal_37d1e126-bda0-4d33-9787-35e8548166e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_09f8c56b-29ef-4dfa-adb1-50a0de84e30f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_df039359-ef1f-43d1-9d71-4d5b8b2e38e8" xlink:to="loc_us-gaap_InterestExpenseDebt_09f8c56b-29ef-4dfa-adb1-50a0de84e30f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_4bfa0dde-497d-444b-bc97-fe0311aaa9cf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmortizationOfFinancingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_df039359-ef1f-43d1-9d71-4d5b8b2e38e8" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_4bfa0dde-497d-444b-bc97-fe0311aaa9cf" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/DebtRevolvingCreditFacilitiesDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#DebtRevolvingCreditFacilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/DebtRevolvingCreditFacilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_edd66cef-c36c-4808-a697-6447fc637ee0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_d692293d-c53d-4f2b-acfc-7ac83766e6ba" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_edd66cef-c36c-4808-a697-6447fc637ee0" xlink:to="loc_us-gaap_DebtInstrumentTable_d692293d-c53d-4f2b-acfc-7ac83766e6ba" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_0a61a49b-87ae-43e9-99c6-6b4aca7d17d7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d692293d-c53d-4f2b-acfc-7ac83766e6ba" xlink:to="loc_us-gaap_CreditFacilityAxis_0a61a49b-87ae-43e9-99c6-6b4aca7d17d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_0a61a49b-87ae-43e9-99c6-6b4aca7d17d7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_0a61a49b-87ae-43e9-99c6-6b4aca7d17d7" xlink:to="loc_us-gaap_CreditFacilityDomain_0a61a49b-87ae-43e9-99c6-6b4aca7d17d7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_4954167c-d038-4903-886c-dc9c7c4b9987" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_0a61a49b-87ae-43e9-99c6-6b4aca7d17d7" xlink:to="loc_us-gaap_CreditFacilityDomain_4954167c-d038-4903-886c-dc9c7c4b9987" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_749c9466-d94b-4f92-bba3-6bbfc96eab59" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_4954167c-d038-4903-886c-dc9c7c4b9987" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_749c9466-d94b-4f92-bba3-6bbfc96eab59" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_3568e861-0c3e-4146-b832-d11f53ee2d63" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d692293d-c53d-4f2b-acfc-7ac83766e6ba" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_3568e861-0c3e-4146-b832-d11f53ee2d63" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3568e861-0c3e-4146-b832-d11f53ee2d63_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_3568e861-0c3e-4146-b832-d11f53ee2d63" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3568e861-0c3e-4146-b832-d11f53ee2d63_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_8df4e29c-5825-452a-bde9-d9ce1aaa0aea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_3568e861-0c3e-4146-b832-d11f53ee2d63" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_8df4e29c-5825-452a-bde9-d9ce1aaa0aea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_00a4e45e-bd7e-4961-b7d9-02bd8837e02b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_8df4e29c-5825-452a-bde9-d9ce1aaa0aea" xlink:to="loc_us-gaap_LineOfCreditMember_00a4e45e-bd7e-4961-b7d9-02bd8837e02b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_d3b361ae-94a3-4ee6-bc33-ce8d20afec3a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d692293d-c53d-4f2b-acfc-7ac83766e6ba" xlink:to="loc_us-gaap_VariableRateAxis_d3b361ae-94a3-4ee6-bc33-ce8d20afec3a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_d3b361ae-94a3-4ee6-bc33-ce8d20afec3a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_d3b361ae-94a3-4ee6-bc33-ce8d20afec3a" xlink:to="loc_us-gaap_VariableRateDomain_d3b361ae-94a3-4ee6-bc33-ce8d20afec3a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_e540a126-dce2-4b03-90b2-106eb53fe823" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_d3b361ae-94a3-4ee6-bc33-ce8d20afec3a" xlink:to="loc_us-gaap_VariableRateDomain_e540a126-dce2-4b03-90b2-106eb53fe823" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_5d0b6fb1-370c-4b94-b343-b65933c7e2ef" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_e540a126-dce2-4b03-90b2-106eb53fe823" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_5d0b6fb1-370c-4b94-b343-b65933c7e2ef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_ff7d57e3-6cfd-47a1-a709-0e9795938fe0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_e540a126-dce2-4b03-90b2-106eb53fe823" xlink:to="loc_us-gaap_BaseRateMember_ff7d57e3-6cfd-47a1-a709-0e9795938fe0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_87528600-6332-4c67-b0d3-2dc9a91f5d87" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_edd66cef-c36c-4808-a697-6447fc637ee0" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_87528600-6332-4c67-b0d3-2dc9a91f5d87" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_aab491ee-d7e1-4ced-a074-1292a3ceaef5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_edd66cef-c36c-4808-a697-6447fc637ee0" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_aab491ee-d7e1-4ced-a074-1292a3ceaef5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_5ecb6f63-3250-41d9-ae5b-35df8e1128c8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_edd66cef-c36c-4808-a697-6447fc637ee0" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_5ecb6f63-3250-41d9-ae5b-35df8e1128c8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_e8486261-5e50-4c8a-b3ad-695f2f89a355" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_edd66cef-c36c-4808-a697-6447fc637ee0" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_e8486261-5e50-4c8a-b3ad-695f2f89a355" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_a4370c2d-d517-4fe4-98d1-29c84a1e17f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_edd66cef-c36c-4808-a697-6447fc637ee0" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_a4370c2d-d517-4fe4-98d1-29c84a1e17f6" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/SegmentReportingDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#SegmentReportingDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/SegmentReportingDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingRevenueReconcilingItemLineItems_7930719c-f2e9-4832-969a-52f20a7db888" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingRevenueReconcilingItemLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable_320ca87a-ae36-4fb8-9863-09993bf24cbf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingRevenueReconcilingItemLineItems_7930719c-f2e9-4832-969a-52f20a7db888" xlink:to="loc_us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable_320ca87a-ae36-4fb8-9863-09993bf24cbf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_bcd563c6-c275-4271-bc30-3913bbe3fb35" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable_320ca87a-ae36-4fb8-9863-09993bf24cbf" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_bcd563c6-c275-4271-bc30-3913bbe3fb35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_bcd563c6-c275-4271-bc30-3913bbe3fb35_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_bcd563c6-c275-4271-bc30-3913bbe3fb35" xlink:to="loc_us-gaap_SegmentDomain_bcd563c6-c275-4271-bc30-3913bbe3fb35_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_28ca72fd-0208-42a3-950c-41b263ac23c7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_bcd563c6-c275-4271-bc30-3913bbe3fb35" xlink:to="loc_us-gaap_SegmentDomain_28ca72fd-0208-42a3-950c-41b263ac23c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_ReportableSegmentMember_92127c5f-1615-4d1c-b92b-37a00a71c3b8" xlink:href="sndk-20251003.xsd#sndk_ReportableSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_28ca72fd-0208-42a3-950c-41b263ac23c7" xlink:to="loc_sndk_ReportableSegmentMember_92127c5f-1615-4d1c-b92b-37a00a71c3b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_b9ec9c2d-2049-4e32-aff5-a154380b9ef4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingRevenueReconcilingItemLineItems_7930719c-f2e9-4832-969a-52f20a7db888" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_b9ec9c2d-2049-4e32-aff5-a154380b9ef4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_CostOfGoodsAndServiceAdjusted_fa85205e-d765-4d55-a979-2485a4373e37" xlink:href="sndk-20251003.xsd#sndk_CostOfGoodsAndServiceAdjusted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingRevenueReconcilingItemLineItems_7930719c-f2e9-4832-969a-52f20a7db888" xlink:to="loc_sndk_CostOfGoodsAndServiceAdjusted_fa85205e-d765-4d55-a979-2485a4373e37" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_OperatingExpensesAdjusted_0e5f37af-aa7e-465c-ad6f-5a23df36def8" xlink:href="sndk-20251003.xsd#sndk_OperatingExpensesAdjusted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingRevenueReconcilingItemLineItems_7930719c-f2e9-4832-969a-52f20a7db888" xlink:to="loc_sndk_OperatingExpensesAdjusted_0e5f37af-aa7e-465c-ad6f-5a23df36def8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_b665822a-8d63-4585-8f57-4ebd52e1cb11" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingRevenueReconcilingItemLineItems_7930719c-f2e9-4832-969a-52f20a7db888" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_b665822a-8d63-4585-8f57-4ebd52e1cb11" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_9b7b2dc8-6a04-43a5-9069-1b8596af2d59" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingRevenueReconcilingItemLineItems_7930719c-f2e9-4832-969a-52f20a7db888" xlink:to="loc_us-gaap_RestructuringCharges_9b7b2dc8-6a04-43a5-9069-1b8596af2d59" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_BusinessSeparationCosts_7a0a72b6-0c95-4206-8770-c23be493d35e" xlink:href="sndk-20251003.xsd#sndk_BusinessSeparationCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingRevenueReconcilingItemLineItems_7930719c-f2e9-4832-969a-52f20a7db888" xlink:to="loc_sndk_BusinessSeparationCosts_7a0a72b6-0c95-4206-8770-c23be493d35e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_00af8cbe-b645-41b4-b213-14052c3cdfa8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingRevenueReconcilingItemLineItems_7930719c-f2e9-4832-969a-52f20a7db888" xlink:to="loc_us-gaap_GainLossOnSaleOfBusiness_00af8cbe-b645-41b4-b213-14052c3cdfa8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_40bfb172-aaa2-4d5d-b9a9-9e7c1d219699" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingRevenueReconcilingItemLineItems_7930719c-f2e9-4832-969a-52f20a7db888" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_40bfb172-aaa2-4d5d-b9a9-9e7c1d219699" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_dd55384f-2228-4414-91ae-7f96b1873f04" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingRevenueReconcilingItemLineItems_7930719c-f2e9-4832-969a-52f20a7db888" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_dd55384f-2228-4414-91ae-7f96b1873f04" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_be748a1f-9fe6-4718-a345-00ec589fa387" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingRevenueReconcilingItemLineItems_7930719c-f2e9-4832-969a-52f20a7db888" xlink:to="loc_us-gaap_NetIncomeLoss_be748a1f-9fe6-4718-a345-00ec589fa387" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesScheduleofNotesReceivableandInvestmentsinRelatedPartiesDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesScheduleofNotesReceivableandInvestmentsinRelatedPartiesDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesScheduleofNotesReceivableandInvestmentsinRelatedPartiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_36f94bd8-5827-49c4-8fe5-722862f09183" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_1c68ba5e-d724-4778-9256-549e1d861710" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_36f94bd8-5827-49c4-8fe5-722862f09183" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_1c68ba5e-d724-4778-9256-549e1d861710" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_18b6e03c-ded5-4800-b886-606801620169" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_1c68ba5e-d724-4778-9256-549e1d861710" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_18b6e03c-ded5-4800-b886-606801620169" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_18b6e03c-ded5-4800-b886-606801620169_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LegalEntityTypeOfCounterpartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_18b6e03c-ded5-4800-b886-606801620169" xlink:to="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_18b6e03c-ded5-4800-b886-606801620169_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_49f95960-8230-44f5-86a4-100895d4fed7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LegalEntityTypeOfCounterpartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_18b6e03c-ded5-4800-b886-606801620169" xlink:to="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_49f95960-8230-44f5-86a4-100895d4fed7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_ff153fbf-d92b-40d6-a4e8-b1d15722bf0f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_49f95960-8230-44f5-86a4-100895d4fed7" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_ff153fbf-d92b-40d6-a4e8-b1d15722bf0f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_FlashPartnersLtdMember_81160c67-c6ad-4abd-bbe8-bf6f360516c1" xlink:href="sndk-20251003.xsd#sndk_FlashPartnersLtdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeMember_ff153fbf-d92b-40d6-a4e8-b1d15722bf0f" xlink:to="loc_sndk_FlashPartnersLtdMember_81160c67-c6ad-4abd-bbe8-bf6f360516c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_FlashAllianceLtdMember_5e383c7b-9a0a-48b0-a548-d5fa07e55f98" xlink:href="sndk-20251003.xsd#sndk_FlashAllianceLtdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeMember_ff153fbf-d92b-40d6-a4e8-b1d15722bf0f" xlink:to="loc_sndk_FlashAllianceLtdMember_5e383c7b-9a0a-48b0-a548-d5fa07e55f98" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_FlashForwardLtdMember_f32ea166-3a68-4a04-b238-8ae8a640378d" xlink:href="sndk-20251003.xsd#sndk_FlashForwardLtdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeMember_ff153fbf-d92b-40d6-a4e8-b1d15722bf0f" xlink:to="loc_sndk_FlashForwardLtdMember_f32ea166-3a68-4a04-b238-8ae8a640378d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5bda4291-a9b7-4c5c-b253-57a350d5e64a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_1c68ba5e-d724-4778-9256-549e1d861710" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5bda4291-a9b7-4c5c-b253-57a350d5e64a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_5bda4291-a9b7-4c5c-b253-57a350d5e64a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5bda4291-a9b7-4c5c-b253-57a350d5e64a" xlink:to="loc_us-gaap_RelatedPartyDomain_5bda4291-a9b7-4c5c-b253-57a350d5e64a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_55d8fdb1-c2c1-4258-a7fb-63b66b043409" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5bda4291-a9b7-4c5c-b253-57a350d5e64a" xlink:to="loc_us-gaap_RelatedPartyDomain_55d8fdb1-c2c1-4258-a7fb-63b66b043409" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_c0625d5b-35e3-49b6-aeab-00903559acdb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_55d8fdb1-c2c1-4258-a7fb-63b66b043409" xlink:to="loc_us-gaap_RelatedPartyMember_c0625d5b-35e3-49b6-aeab-00903559acdb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableNet_2ce1a32f-6b32-468e-ae82-1f0f0379df96" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NotesReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_36f94bd8-5827-49c4-8fe5-722862f09183" xlink:to="loc_us-gaap_NotesReceivableNet_2ce1a32f-6b32-468e-ae82-1f0f0379df96" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Investments_2d06b43c-76c8-49a0-9b8d-74c0a872e71d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Investments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_36f94bd8-5827-49c4-8fe5-722862f09183" xlink:to="loc_us-gaap_Investments_2d06b43c-76c8-49a0-9b8d-74c0a872e71d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_NotesReceivableAndInvestmentsInRelatedPartiesNoncurrent_4c877b0d-1080-4d3a-8d92-c85c7d2278d4" xlink:href="sndk-20251003.xsd#sndk_NotesReceivableAndInvestmentsInRelatedPartiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_36f94bd8-5827-49c4-8fe5-722862f09183" xlink:to="loc_sndk_NotesReceivableAndInvestmentsInRelatedPartiesNoncurrent_4c877b0d-1080-4d3a-8d92-c85c7d2278d4" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesAdditionalInformationDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_36796972-8608-4a01-9e85-db7a15d7e68c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_36796972-8608-4a01-9e85-db7a15d7e68c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_4df7b9e8-71f6-4bb9-8c19-909a77c6e7f1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_36796972-8608-4a01-9e85-db7a15d7e68c" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_4df7b9e8-71f6-4bb9-8c19-909a77c6e7f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_4df7b9e8-71f6-4bb9-8c19-909a77c6e7f1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LegalEntityTypeOfCounterpartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_4df7b9e8-71f6-4bb9-8c19-909a77c6e7f1" xlink:to="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_4df7b9e8-71f6-4bb9-8c19-909a77c6e7f1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_db93ffc3-fc7d-4324-9a9b-6ff2c3ce8bad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LegalEntityTypeOfCounterpartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis_4df7b9e8-71f6-4bb9-8c19-909a77c6e7f1" xlink:to="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_db93ffc3-fc7d-4324-9a9b-6ff2c3ce8bad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_b35487f5-935a-49a8-9aa3-ea79d9f0d4ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LegalEntityTypeOfCounterpartyDomain_db93ffc3-fc7d-4324-9a9b-6ff2c3ce8bad" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_b35487f5-935a-49a8-9aa3-ea79d9f0d4ad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_b6554d8d-924b-47c7-828a-f0c4f6d05477" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_36796972-8608-4a01-9e85-db7a15d7e68c" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_b6554d8d-924b-47c7-828a-f0c4f6d05477" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_b6554d8d-924b-47c7-828a-f0c4f6d05477_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_b6554d8d-924b-47c7-828a-f0c4f6d05477" xlink:to="loc_us-gaap_RelatedPartyDomain_b6554d8d-924b-47c7-828a-f0c4f6d05477_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_dd0c75ae-dffe-4744-9bd1-4dc5b586db8d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_b6554d8d-924b-47c7-828a-f0c4f6d05477" xlink:to="loc_us-gaap_RelatedPartyDomain_dd0c75ae-dffe-4744-9bd1-4dc5b586db8d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_d20d0084-b222-4f92-a949-bcd6eb10cbeb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_dd0c75ae-dffe-4744-9bd1-4dc5b586db8d" xlink:to="loc_us-gaap_RelatedPartyMember_d20d0084-b222-4f92-a949-bcd6eb10cbeb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_043e8f6c-365e-4506-b610-0b5ee3fb6a9e" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_36796972-8608-4a01-9e85-db7a15d7e68c" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_043e8f6c-365e-4506-b610-0b5ee3fb6a9e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_043e8f6c-365e-4506-b610-0b5ee3fb6a9e_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_043e8f6c-365e-4506-b610-0b5ee3fb6a9e" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_043e8f6c-365e-4506-b610-0b5ee3fb6a9e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_b966809a-64ba-4e23-9ec0-99683adbddeb" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_043e8f6c-365e-4506-b610-0b5ee3fb6a9e" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_b966809a-64ba-4e23-9ec0-99683adbddeb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_FlashVenturesMember_f74a180c-e4e6-4591-b82e-a77584e6672d" xlink:href="sndk-20251003.xsd#sndk_FlashVenturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_b966809a-64ba-4e23-9ec0-99683adbddeb" xlink:to="loc_sndk_FlashVenturesMember_f74a180c-e4e6-4591-b82e-a77584e6672d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_K1K2AndY7FacilitiesMember_86c33a8b-fb68-4aca-9d4c-99a469aedb25" xlink:href="sndk-20251003.xsd#sndk_K1K2AndY7FacilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_b966809a-64ba-4e23-9ec0-99683adbddeb" xlink:to="loc_sndk_K1K2AndY7FacilitiesMember_86c33a8b-fb68-4aca-9d4c-99a469aedb25" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_66c0336e-c716-4628-925b-c8c87ba7290a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_36796972-8608-4a01-9e85-db7a15d7e68c" xlink:to="loc_srt_RangeAxis_66c0336e-c716-4628-925b-c8c87ba7290a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_66c0336e-c716-4628-925b-c8c87ba7290a_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_66c0336e-c716-4628-925b-c8c87ba7290a" xlink:to="loc_srt_RangeMember_66c0336e-c716-4628-925b-c8c87ba7290a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_b6c50899-085b-4df2-a1f3-1adaebcdff87" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_66c0336e-c716-4628-925b-c8c87ba7290a" xlink:to="loc_srt_RangeMember_b6c50899-085b-4df2-a1f3-1adaebcdff87" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_4928c351-9e35-49a8-b720-642070daf92a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_b6c50899-085b-4df2-a1f3-1adaebcdff87" xlink:to="loc_srt_MaximumMember_4928c351-9e35-49a8-b720-642070daf92a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsAxis_e8a43133-995a-46af-9846-4201a4a076c1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCommitmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_36796972-8608-4a01-9e85-db7a15d7e68c" xlink:to="loc_us-gaap_OtherCommitmentsAxis_e8a43133-995a-46af-9846-4201a4a076c1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_e8a43133-995a-46af-9846-4201a4a076c1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherCommitmentsAxis_e8a43133-995a-46af-9846-4201a4a076c1" xlink:to="loc_us-gaap_OtherCommitmentsDomain_e8a43133-995a-46af-9846-4201a4a076c1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_ee3ff705-c3dd-487e-ad8d-538298583fc8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherCommitmentsAxis_e8a43133-995a-46af-9846-4201a4a076c1" xlink:to="loc_us-gaap_OtherCommitmentsDomain_ee3ff705-c3dd-487e-ad8d-538298583fc8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_FutureBuildingDepreciationPaymentsMember_7c118b17-932b-470c-afc4-6f4486a69021" xlink:href="sndk-20251003.xsd#sndk_FutureBuildingDepreciationPaymentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_ee3ff705-c3dd-487e-ad8d-538298583fc8" xlink:to="loc_sndk_FutureBuildingDepreciationPaymentsMember_7c118b17-932b-470c-afc4-6f4486a69021" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_7e246906-ba20-4445-9671-33a8376e4225" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_36796972-8608-4a01-9e85-db7a15d7e68c" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_7e246906-ba20-4445-9671-33a8376e4225" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_7e246906-ba20-4445-9671-33a8376e4225_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_7e246906-ba20-4445-9671-33a8376e4225" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_7e246906-ba20-4445-9671-33a8376e4225_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_0669370d-9cd4-4067-a36b-49eb67803a3f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_7e246906-ba20-4445-9671-33a8376e4225" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_0669370d-9cd4-4067-a36b-49eb67803a3f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCurrentAssetsMember_82f72f8b-806d-4621-a9d9-fd3de78a5428" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_0669370d-9cd4-4067-a36b-49eb67803a3f" xlink:to="loc_us-gaap_OtherCurrentAssetsMember_82f72f8b-806d-4621-a9d9-fd3de78a5428" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentAssetsMember_bd34775d-257d-4042-a4d8-bc9895ecd569" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNoncurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_0669370d-9cd4-4067-a36b-49eb67803a3f" xlink:to="loc_us-gaap_OtherNoncurrentAssetsMember_bd34775d-257d-4042-a4d8-bc9895ecd569" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_28734fe2-aeee-4018-882e-814f85906efd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_36796972-8608-4a01-9e85-db7a15d7e68c" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_28734fe2-aeee-4018-882e-814f85906efd" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_28734fe2-aeee-4018-882e-814f85906efd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_28734fe2-aeee-4018-882e-814f85906efd" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_28734fe2-aeee-4018-882e-814f85906efd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_7909d2db-3fdf-4424-b91e-af4c95ffa665" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_28734fe2-aeee-4018-882e-814f85906efd" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_7909d2db-3fdf-4424-b91e-af4c95ffa665" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_ResearchAndDevelopmentCommitmentsMember_e089aa9f-84da-457a-b829-1715c45aa893" xlink:href="sndk-20251003.xsd#sndk_ResearchAndDevelopmentCommitmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_7909d2db-3fdf-4424-b91e-af4c95ffa665" xlink:to="loc_sndk_ResearchAndDevelopmentCommitmentsMember_e089aa9f-84da-457a-b829-1715c45aa893" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_ReimbursementOfShortTermEmployeeIncentivesMember_2b58c33a-b2be-4a74-b0fc-430da5ac8a5a" xlink:href="sndk-20251003.xsd#sndk_ReimbursementOfShortTermEmployeeIncentivesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_7909d2db-3fdf-4424-b91e-af4c95ffa665" xlink:to="loc_sndk_ReimbursementOfShortTermEmployeeIncentivesMember_2b58c33a-b2be-4a74-b0fc-430da5ac8a5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_3cfd0e58-b4a8-494d-ae95-98d8991f0e60" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_36796972-8608-4a01-9e85-db7a15d7e68c" xlink:to="loc_srt_CounterpartyNameAxis_3cfd0e58-b4a8-494d-ae95-98d8991f0e60" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3cfd0e58-b4a8-494d-ae95-98d8991f0e60_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_3cfd0e58-b4a8-494d-ae95-98d8991f0e60" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3cfd0e58-b4a8-494d-ae95-98d8991f0e60_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_6eda829e-98b4-468d-809f-64e20c70e998" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_3cfd0e58-b4a8-494d-ae95-98d8991f0e60" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_6eda829e-98b4-468d-809f-64e20c70e998" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_WDCSubsidiariesMember_8cd9b7e1-5d2a-4718-aa21-e8a3e08d3b34" xlink:href="sndk-20251003.xsd#sndk_WDCSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_6eda829e-98b4-468d-809f-64e20c70e998" xlink:to="loc_sndk_WDCSubsidiariesMember_8cd9b7e1-5d2a-4718-aa21-e8a3e08d3b34" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_76fa1462-8f74-477d-8f37-3779b1b6a063" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_76fa1462-8f74-477d-8f37-3779b1b6a063" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_086b1943-647e-44ae-b9aa-f51b16d57172" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_086b1943-647e-44ae-b9aa-f51b16d57172" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_5f957a5c-91de-4d99-a208-cd63eaf06c21" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_us-gaap_AccountsPayableCurrent_5f957a5c-91de-4d99-a208-cd63eaf06c21" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_InvestmentFundingCommitments_4296161a-55ba-4bd1-886e-5fafeb8d264c" xlink:href="sndk-20251003.xsd#sndk_InvestmentFundingCommitments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_sndk_InvestmentFundingCommitments_4296161a-55ba-4bd1-886e-5fafeb8d264c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_5e1be289-3326-4777-94e0-d43519bfbf81" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_5e1be289-3326-4777-94e0-d43519bfbf81" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_ManufacturingCapacityPercentOperating_186b3425-0512-4875-bf9d-bebc976754cb" xlink:href="sndk-20251003.xsd#sndk_ManufacturingCapacityPercentOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_sndk_ManufacturingCapacityPercentOperating_186b3425-0512-4875-bf9d-bebc976754cb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_CostsAssociatedWithUnderutilizedCapacityAsAResultOfATemporaryAbnormalReductionInProduction_abef3f3f-497c-44e1-b578-76900e1f7e7c" xlink:href="sndk-20251003.xsd#sndk_CostsAssociatedWithUnderutilizedCapacityAsAResultOfATemporaryAbnormalReductionInProduction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_sndk_CostsAssociatedWithUnderutilizedCapacityAsAResultOfATemporaryAbnormalReductionInProduction_abef3f3f-497c-44e1-b578-76900e1f7e7c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitment_3058ad26-2a25-4b71-aa67-09c79799456b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCommitment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_us-gaap_OtherCommitment_3058ad26-2a25-4b71-aa67-09c79799456b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_OtherCommitmentExchangeRate_b22bc3e4-33a2-469b-a4d3-c6088c299061" xlink:href="sndk-20251003.xsd#sndk_OtherCommitmentExchangeRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_sndk_OtherCommitmentExchangeRate_b22bc3e4-33a2-469b-a4d3-c6088c299061" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsFutureMinimumPaymentsRemainderOfFiscalYear_a02a56d0-31bc-4590-8109-46f3c6b1f5be" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCommitmentsFutureMinimumPaymentsRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_us-gaap_OtherCommitmentsFutureMinimumPaymentsRemainderOfFiscalYear_a02a56d0-31bc-4590-8109-46f3c6b1f5be" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentDueInNextTwelveMonths_8e97ac4e-cbc4-4fb3-b4a4-bc900f08f7a9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCommitmentDueInNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_us-gaap_OtherCommitmentDueInNextTwelveMonths_8e97ac4e-cbc4-4fb3-b4a4-bc900f08f7a9" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentDueInSecondYear_fe08b2b8-ef39-4fd2-999d-bdf62206b770" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCommitmentDueInSecondYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_us-gaap_OtherCommitmentDueInSecondYear_fe08b2b8-ef39-4fd2-999d-bdf62206b770" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentDueInThirdYear_dfc07cb2-0272-4680-bbcb-433239da72ca" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCommitmentDueInThirdYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_us-gaap_OtherCommitmentDueInThirdYear_dfc07cb2-0272-4680-bbcb-433239da72ca" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_f2724bc7-bfec-469f-bcb8-3de517a80627" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_f2724bc7-bfec-469f-bcb8-3de517a80627" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_TaxLiabilityIndemnification_7c2fc5f8-97e4-46d5-b01b-ec1103d3b782" xlink:href="sndk-20251003.xsd#sndk_TaxLiabilityIndemnification"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_sndk_TaxLiabilityIndemnification_7c2fc5f8-97e4-46d5-b01b-ec1103d3b782" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_NotesPayableNet_39d6bc59-21af-44a2-ad49-e9d00d3ace1a" xlink:href="sndk-20251003.xsd#sndk_NotesPayableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_sndk_NotesPayableNet_39d6bc59-21af-44a2-ad49-e9d00d3ace1a" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfDebt_65a90e4d-f3cd-48e3-8887-16d45686b2f1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_f683b7c7-bd06-40f6-9125-55be461f5bc2" xlink:to="loc_us-gaap_RepaymentsOfDebt_65a90e4d-f3cd-48e3-8887-16d45686b2f1" xlink:type="arc" order="16"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesScheduleofVariableInterestEntityMaximumLossExposureDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesScheduleofVariableInterestEntityMaximumLossExposureDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesScheduleofVariableInterestEntityMaximumLossExposureDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsLineItems_3644be57-76b9-4c95-9d0f-05534eb7d439" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_35f4f1c3-c7d1-493b-a05e-be22c876ad14" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfGuaranteeObligationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_3644be57-76b9-4c95-9d0f-05534eb7d439" xlink:to="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_35f4f1c3-c7d1-493b-a05e-be22c876ad14" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_954494c8-4a01-410e-ae80-fe812824c33d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_35f4f1c3-c7d1-493b-a05e-be22c876ad14" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_954494c8-4a01-410e-ae80-fe812824c33d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_954494c8-4a01-410e-ae80-fe812824c33d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_954494c8-4a01-410e-ae80-fe812824c33d" xlink:to="loc_us-gaap_RelatedPartyDomain_954494c8-4a01-410e-ae80-fe812824c33d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_b8073df1-87ab-4c45-854f-eecf1e865aff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_954494c8-4a01-410e-ae80-fe812824c33d" xlink:to="loc_us-gaap_RelatedPartyDomain_b8073df1-87ab-4c45-854f-eecf1e865aff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_52498f32-69f0-4fec-9567-45cadcfc762f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_b8073df1-87ab-4c45-854f-eecf1e865aff" xlink:to="loc_us-gaap_RelatedPartyMember_52498f32-69f0-4fec-9567-45cadcfc762f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_fd6d1fde-95ce-460c-88b7-ed52f4b99f92" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_35f4f1c3-c7d1-493b-a05e-be22c876ad14" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_fd6d1fde-95ce-460c-88b7-ed52f4b99f92" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_fd6d1fde-95ce-460c-88b7-ed52f4b99f92_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_fd6d1fde-95ce-460c-88b7-ed52f4b99f92" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_fd6d1fde-95ce-460c-88b7-ed52f4b99f92_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_55a676cd-4beb-4bce-bd0d-e6af1251bece" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_fd6d1fde-95ce-460c-88b7-ed52f4b99f92" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_55a676cd-4beb-4bce-bd0d-e6af1251bece" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableMember_98221985-7d60-4aa1-af44-3187d97a09db" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NotesReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_55a676cd-4beb-4bce-bd0d-e6af1251bece" xlink:to="loc_us-gaap_NotesReceivableMember_98221985-7d60-4aa1-af44-3187d97a09db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentsMember_c3acc488-5a98-4ed7-944c-372bd8e3b4f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_55a676cd-4beb-4bce-bd0d-e6af1251bece" xlink:to="loc_us-gaap_EquityMethodInvestmentsMember_c3acc488-5a98-4ed7-944c-372bd8e3b4f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_f3be181f-824e-4837-91ba-0a60d0f61657" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_3644be57-76b9-4c95-9d0f-05534eb7d439" xlink:to="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_f3be181f-824e-4837-91ba-0a60d0f61657" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_d8b1da82-05d8-49ac-aff8-90444b67e979" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_3644be57-76b9-4c95-9d0f-05534eb7d439" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_d8b1da82-05d8-49ac-aff8-90444b67e979" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryGross_9c0395c6-f406-45fe-b829-70b2ac84d259" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_3644be57-76b9-4c95-9d0f-05534eb7d439" xlink:to="loc_us-gaap_InventoryGross_9c0395c6-f406-45fe-b829-70b2ac84d259" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesScheduleofGuarantorObligationsDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesScheduleofGuarantorObligationsDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesScheduleofGuarantorObligationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_ff775400-b369-4c9d-88ea-206134059917" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_4b0a157a-6208-4c61-b9ee-e673a969cea2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_ff775400-b369-4c9d-88ea-206134059917" xlink:to="loc_us-gaap_LossContingenciesTable_4b0a157a-6208-4c61-b9ee-e673a969cea2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_c4ac9dee-ed99-4366-8883-5081265a7e96" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_4b0a157a-6208-4c61-b9ee-e673a969cea2" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_c4ac9dee-ed99-4366-8883-5081265a7e96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_c4ac9dee-ed99-4366-8883-5081265a7e96_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_c4ac9dee-ed99-4366-8883-5081265a7e96" xlink:to="loc_us-gaap_RelatedPartyDomain_c4ac9dee-ed99-4366-8883-5081265a7e96_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_90713b61-acb0-4f29-9fcd-66691da26e5a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_c4ac9dee-ed99-4366-8883-5081265a7e96" xlink:to="loc_us-gaap_RelatedPartyDomain_90713b61-acb0-4f29-9fcd-66691da26e5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_1a675e73-ec36-4a24-b257-5284fe2d8e3f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_90713b61-acb0-4f29-9fcd-66691da26e5a" xlink:to="loc_us-gaap_RelatedPartyMember_1a675e73-ec36-4a24-b257-5284fe2d8e3f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_b03bd680-1477-421d-82d0-21f690bb6175" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_ff775400-b369-4c9d-88ea-206134059917" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_b03bd680-1477-421d-82d0-21f690bb6175" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesScheduleofRemainingGuaranteeObligationsDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesScheduleofRemainingGuaranteeObligationsDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesScheduleofRemainingGuaranteeObligationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsLineItems_18415647-0077-4095-b13e-907c09dbbc85" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_3472e9d4-9029-454b-9d08-d0fbc42ebcc7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfGuaranteeObligationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_18415647-0077-4095-b13e-907c09dbbc85" xlink:to="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_3472e9d4-9029-454b-9d08-d0fbc42ebcc7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1ab99719-c91b-466b-ba90-fe17aa909b7b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_3472e9d4-9029-454b-9d08-d0fbc42ebcc7" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1ab99719-c91b-466b-ba90-fe17aa909b7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_1ab99719-c91b-466b-ba90-fe17aa909b7b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1ab99719-c91b-466b-ba90-fe17aa909b7b" xlink:to="loc_us-gaap_RelatedPartyDomain_1ab99719-c91b-466b-ba90-fe17aa909b7b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_df4924f8-5be1-49ef-b67d-431cc51c84f3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1ab99719-c91b-466b-ba90-fe17aa909b7b" xlink:to="loc_us-gaap_RelatedPartyDomain_df4924f8-5be1-49ef-b67d-431cc51c84f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_bff97a9e-61c6-47c8-a9af-365abaf1f86a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_df4924f8-5be1-49ef-b67d-431cc51c84f3" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_bff97a9e-61c6-47c8-a9af-365abaf1f86a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsByNatureAxis_221a7272-c6b2-4db0-8cfc-578cede97765" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsByNatureAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_3472e9d4-9029-454b-9d08-d0fbc42ebcc7" xlink:to="loc_us-gaap_GuaranteeObligationsByNatureAxis_221a7272-c6b2-4db0-8cfc-578cede97765" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_221a7272-c6b2-4db0-8cfc-578cede97765_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_221a7272-c6b2-4db0-8cfc-578cede97765" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_221a7272-c6b2-4db0-8cfc-578cede97765_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_d5e51fd3-cdcc-4672-bac0-9e465bdd68d8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_221a7272-c6b2-4db0-8cfc-578cede97765" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_d5e51fd3-cdcc-4672-bac0-9e465bdd68d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_PaymentOfPrincipalAmortizationMember_793ed041-47d4-432c-b1ba-66743e0ad239" xlink:href="sndk-20251003.xsd#sndk_PaymentOfPrincipalAmortizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_d5e51fd3-cdcc-4672-bac0-9e465bdd68d8" xlink:to="loc_sndk_PaymentOfPrincipalAmortizationMember_793ed041-47d4-432c-b1ba-66743e0ad239" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_PurchaseOptionExercisePriceMember_8a0884df-4320-4152-919f-0d488504bd41" xlink:href="sndk-20251003.xsd#sndk_PurchaseOptionExercisePriceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_d5e51fd3-cdcc-4672-bac0-9e465bdd68d8" xlink:to="loc_sndk_PurchaseOptionExercisePriceMember_8a0884df-4320-4152-919f-0d488504bd41" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_GuaranteeObligationsMaximumExposureYearOne_bde58057-c652-4b48-96cc-56c8f014b916" xlink:href="sndk-20251003.xsd#sndk_GuaranteeObligationsMaximumExposureYearOne"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_18415647-0077-4095-b13e-907c09dbbc85" xlink:to="loc_sndk_GuaranteeObligationsMaximumExposureYearOne_bde58057-c652-4b48-96cc-56c8f014b916" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_GuaranteeObligationsMaximumExposureYearTwo_bcce84ae-5769-47cd-a4a0-549c9acc7f6c" xlink:href="sndk-20251003.xsd#sndk_GuaranteeObligationsMaximumExposureYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_18415647-0077-4095-b13e-907c09dbbc85" xlink:to="loc_sndk_GuaranteeObligationsMaximumExposureYearTwo_bcce84ae-5769-47cd-a4a0-549c9acc7f6c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_GuaranteeObligationsMaximumExposureYearThree_9bef21fb-444f-48db-98df-2e85e6004404" xlink:href="sndk-20251003.xsd#sndk_GuaranteeObligationsMaximumExposureYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_18415647-0077-4095-b13e-907c09dbbc85" xlink:to="loc_sndk_GuaranteeObligationsMaximumExposureYearThree_9bef21fb-444f-48db-98df-2e85e6004404" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_GuaranteeObligationsMaximumExposureYearFour_aff4d1e7-aa86-4328-956f-7b963c7d74a2" xlink:href="sndk-20251003.xsd#sndk_GuaranteeObligationsMaximumExposureYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_18415647-0077-4095-b13e-907c09dbbc85" xlink:to="loc_sndk_GuaranteeObligationsMaximumExposureYearFour_aff4d1e7-aa86-4328-956f-7b963c7d74a2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_GuaranteeObligationsMaximumExposureYearFive_5d3f9e6f-3f55-426a-ada7-697cb6ef4c85" xlink:href="sndk-20251003.xsd#sndk_GuaranteeObligationsMaximumExposureYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_18415647-0077-4095-b13e-907c09dbbc85" xlink:to="loc_sndk_GuaranteeObligationsMaximumExposureYearFive_5d3f9e6f-3f55-426a-ada7-697cb6ef4c85" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_GuaranteeObligationsMaximumExposureYearSix_15c13030-fcdb-424f-bd37-2d6d7f0f86f4" xlink:href="sndk-20251003.xsd#sndk_GuaranteeObligationsMaximumExposureYearSix"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_18415647-0077-4095-b13e-907c09dbbc85" xlink:to="loc_sndk_GuaranteeObligationsMaximumExposureYearSix_15c13030-fcdb-424f-bd37-2d6d7f0f86f4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_d9165881-a2f4-4621-933a-d50558fb7602" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_18415647-0077-4095-b13e-907c09dbbc85" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_d9165881-a2f4-4621-933a-d50558fb7602" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesSaleofMajorityInterestDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesSaleofMajorityInterestDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesSaleofMajorityInterestDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e94bd813-9eb0-49b6-a759-fa9d693f8418" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e94bd813-9eb0-49b6-a759-fa9d693f8418" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_7a3d484e-77bb-4af7-aca0-0ec69e5f79d6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e94bd813-9eb0-49b6-a759-fa9d693f8418" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_7a3d484e-77bb-4af7-aca0-0ec69e5f79d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_7a3d484e-77bb-4af7-aca0-0ec69e5f79d6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_7a3d484e-77bb-4af7-aca0-0ec69e5f79d6" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_7a3d484e-77bb-4af7-aca0-0ec69e5f79d6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_f25df701-8a32-46a2-95dd-810aaba99404" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_7a3d484e-77bb-4af7-aca0-0ec69e5f79d6" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_f25df701-8a32-46a2-95dd-810aaba99404" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_d8a29d00-af65-4610-87b0-c732e7530f27" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_f25df701-8a32-46a2-95dd-810aaba99404" xlink:to="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_d8a29d00-af65-4610-87b0-c732e7530f27" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_030359ed-5514-47a6-8eac-d2e7ea481135" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e94bd813-9eb0-49b6-a759-fa9d693f8418" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_030359ed-5514-47a6-8eac-d2e7ea481135" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_030359ed-5514-47a6-8eac-d2e7ea481135_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_030359ed-5514-47a6-8eac-d2e7ea481135" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_030359ed-5514-47a6-8eac-d2e7ea481135_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_0f351d47-4b71-4013-a4e0-a4b9a1474902" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_030359ed-5514-47a6-8eac-d2e7ea481135" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_0f351d47-4b71-4013-a4e0-a4b9a1474902" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_SanDiskSemiconductorShanghaiCo.Ltd.Member_48ec8189-039c-46b7-be13-4e3f46367a7b" xlink:href="sndk-20251003.xsd#sndk_SanDiskSemiconductorShanghaiCo.Ltd.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_0f351d47-4b71-4013-a4e0-a4b9a1474902" xlink:to="loc_sndk_SanDiskSemiconductorShanghaiCo.Ltd.Member_48ec8189-039c-46b7-be13-4e3f46367a7b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_5f3eaf95-1365-4ffa-9af7-ef3377bfb213" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e94bd813-9eb0-49b6-a759-fa9d693f8418" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_5f3eaf95-1365-4ffa-9af7-ef3377bfb213" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_5f3eaf95-1365-4ffa-9af7-ef3377bfb213_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_5f3eaf95-1365-4ffa-9af7-ef3377bfb213" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_5f3eaf95-1365-4ffa-9af7-ef3377bfb213_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_2230205c-0f4c-4bae-8fd4-ed6e63d46c2e" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_5f3eaf95-1365-4ffa-9af7-ef3377bfb213" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_2230205c-0f4c-4bae-8fd4-ed6e63d46c2e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_SanDiskSemiconductorShanghaiCo.Ltd.Member_ae3059ef-5fdd-471a-8210-e225c8d64565" xlink:href="sndk-20251003.xsd#sndk_SanDiskSemiconductorShanghaiCo.Ltd.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_2230205c-0f4c-4bae-8fd4-ed6e63d46c2e" xlink:to="loc_sndk_SanDiskSemiconductorShanghaiCo.Ltd.Member_ae3059ef-5fdd-471a-8210-e225c8d64565" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_0e050d16-d5c3-4ea7-a8c6-1a69541f61a9" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e94bd813-9eb0-49b6-a759-fa9d693f8418" xlink:to="loc_srt_StatementScenarioAxis_0e050d16-d5c3-4ea7-a8c6-1a69541f61a9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_0e050d16-d5c3-4ea7-a8c6-1a69541f61a9_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_0e050d16-d5c3-4ea7-a8c6-1a69541f61a9" xlink:to="loc_srt_ScenarioUnspecifiedDomain_0e050d16-d5c3-4ea7-a8c6-1a69541f61a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_4d77d5a9-ab89-4210-a9e6-2bdcb1fe2119" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_0e050d16-d5c3-4ea7-a8c6-1a69541f61a9" xlink:to="loc_srt_ScenarioUnspecifiedDomain_4d77d5a9-ab89-4210-a9e6-2bdcb1fe2119" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioForecastMember_01778426-8a9c-41cb-8acb-4f80b35a9304" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioForecastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_4d77d5a9-ab89-4210-a9e6-2bdcb1fe2119" xlink:to="loc_srt_ScenarioForecastMember_01778426-8a9c-41cb-8acb-4f80b35a9304" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_7a30806c-3139-4f8e-942c-ee9e651908d6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e94bd813-9eb0-49b6-a759-fa9d693f8418" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_7a30806c-3139-4f8e-942c-ee9e651908d6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_7a30806c-3139-4f8e-942c-ee9e651908d6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_7a30806c-3139-4f8e-942c-ee9e651908d6" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_7a30806c-3139-4f8e-942c-ee9e651908d6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_1a9be11c-9d51-41f8-b9d8-f530ef494c66" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_7a30806c-3139-4f8e-942c-ee9e651908d6" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_1a9be11c-9d51-41f8-b9d8-f530ef494c66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCurrentAssetsMember_7dfc211b-774b-4133-9c51-b550c318240e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_1a9be11c-9d51-41f8-b9d8-f530ef494c66" xlink:to="loc_us-gaap_OtherCurrentAssetsMember_7dfc211b-774b-4133-9c51-b550c318240e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentAssetsMember_7ae403f7-3f50-47f8-96e1-4cbe5b4a4e56" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNoncurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_1a9be11c-9d51-41f8-b9d8-f530ef494c66" xlink:to="loc_us-gaap_OtherNoncurrentAssetsMember_7ae403f7-3f50-47f8-96e1-4cbe5b4a4e56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_98dc3bf2-b3f4-48f2-a9e1-6b9b33aedbea" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e94bd813-9eb0-49b6-a759-fa9d693f8418" xlink:to="loc_srt_CounterpartyNameAxis_98dc3bf2-b3f4-48f2-a9e1-6b9b33aedbea" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_98dc3bf2-b3f4-48f2-a9e1-6b9b33aedbea_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_98dc3bf2-b3f4-48f2-a9e1-6b9b33aedbea" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_98dc3bf2-b3f4-48f2-a9e1-6b9b33aedbea_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8f4cffa2-fa4c-42f0-b377-b8fd1a352025" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_98dc3bf2-b3f4-48f2-a9e1-6b9b33aedbea" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8f4cffa2-fa4c-42f0-b377-b8fd1a352025" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_SanDiskSemiconductorShanghaiCo.Ltd.Member_cd5d04f1-591a-417c-a34e-3ed2db71ffbb" xlink:href="sndk-20251003.xsd#sndk_SanDiskSemiconductorShanghaiCo.Ltd.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8f4cffa2-fa4c-42f0-b377-b8fd1a352025" xlink:to="loc_sndk_SanDiskSemiconductorShanghaiCo.Ltd.Member_cd5d04f1-591a-417c-a34e-3ed2db71ffbb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_1f85cb62-2334-481e-a24e-a67117b6c140" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e94bd813-9eb0-49b6-a759-fa9d693f8418" xlink:to="loc_us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_1f85cb62-2334-481e-a24e-a67117b6c140" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_1f85cb62-2334-481e-a24e-a67117b6c140_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_1f85cb62-2334-481e-a24e-a67117b6c140" xlink:to="loc_us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_1f85cb62-2334-481e-a24e-a67117b6c140_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_203f8d1a-d500-4f10-a401-37e82e810bc0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_1f85cb62-2334-481e-a24e-a67117b6c140" xlink:to="loc_us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_203f8d1a-d500-4f10-a401-37e82e810bc0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_CertainFlashBasedProductsMember_9df01a84-cd05-437b-b941-28972bae2a7f" xlink:href="sndk-20251003.xsd#sndk_CertainFlashBasedProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_203f8d1a-d500-4f10-a401-37e82e810bc0" xlink:to="loc_sndk_CertainFlashBasedProductsMember_9df01a84-cd05-437b-b941-28972bae2a7f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_DisposalGroupPercentOfOwnershipSold_bd5aafb4-5484-4fe6-9ff6-99a36cb69b57" xlink:href="sndk-20251003.xsd#sndk_DisposalGroupPercentOfOwnershipSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_sndk_DisposalGroupPercentOfOwnershipSold_bd5aafb4-5484-4fe6-9ff6-99a36cb69b57" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_7fe9f5e7-e283-485c-a8b0-03136f03901a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_us-gaap_GainLossOnSaleOfBusiness_7fe9f5e7-e283-485c-a8b0-03136f03901a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_1a885da0-e438-413e-b52f-735f5d17a517" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_1a885da0-e438-413e-b52f-735f5d17a517" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents_2b4eab03-3cdd-4f51-b7c2-4d82b892bcc9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents_2b4eab03-3cdd-4f51-b7c2-4d82b892bcc9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwill1_301aaf0b-d5c3-4d1f-970b-1f77f4154494" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwill1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwill1_301aaf0b-d5c3-4d1f-970b-1f77f4154494" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_6a9cfe8d-c08c-45af-bd74-2270d93085b8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_6a9cfe8d-c08c-45af-bd74-2270d93085b8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_902a7a68-2bba-4756-8513-5662a674db37" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromDivestitureOfBusinesses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_902a7a68-2bba-4756-8513-5662a674db37" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_DisposalGroupNumberOfInstallmentPayments_adcea31d-9636-46c7-8027-d0979e6d73b3" xlink:href="sndk-20251003.xsd#sndk_DisposalGroupNumberOfInstallmentPayments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_sndk_DisposalGroupNumberOfInstallmentPayments_adcea31d-9636-46c7-8027-d0979e6d73b3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_DisposalGroupPeriodicPayment_12c9467b-04fb-464d-998d-44a11cfff79f" xlink:href="sndk-20251003.xsd#sndk_DisposalGroupPeriodicPayment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_sndk_DisposalGroupPeriodicPayment_12c9467b-04fb-464d-998d-44a11cfff79f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_DisposalGroupIncludingDiscontinuedOperationConsiderationReceivable_06b62f23-a51a-4b17-92ae-7cd8aac05e98" xlink:href="sndk-20251003.xsd#sndk_DisposalGroupIncludingDiscontinuedOperationConsiderationReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_sndk_DisposalGroupIncludingDiscontinuedOperationConsiderationReceivable_06b62f23-a51a-4b17-92ae-7cd8aac05e98" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_DisposalGroupIncludingDiscontinuedOperationPresentValueDiscount_4503e176-9efe-43f9-bee7-e88ce47c82eb" xlink:href="sndk-20251003.xsd#sndk_DisposalGroupIncludingDiscontinuedOperationPresentValueDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_sndk_DisposalGroupIncludingDiscontinuedOperationPresentValueDiscount_4503e176-9efe-43f9-bee7-e88ce47c82eb" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_DisposalGroupIncludingDiscontinuedOperationPresentValueDiscountEffectiveInterestMethodTerm_848c4b48-65b4-4147-827b-b525510cff63" xlink:href="sndk-20251003.xsd#sndk_DisposalGroupIncludingDiscontinuedOperationPresentValueDiscountEffectiveInterestMethodTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_sndk_DisposalGroupIncludingDiscontinuedOperationPresentValueDiscountEffectiveInterestMethodTerm_848c4b48-65b4-4147-827b-b525510cff63" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_ca7ac9c4-11b1-41bb-839c-20b55e075d0d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_us-gaap_EquityMethodInvestments_ca7ac9c4-11b1-41bb-839c-20b55e075d0d" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermPurchaseCommitmentPeriod_c1b421c9-6da5-447b-b149-0017fb0e066c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermPurchaseCommitmentPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_us-gaap_LongtermPurchaseCommitmentPeriod_c1b421c9-6da5-447b-b149-0017fb0e066c" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermPurchaseCommitmentAmount_b7199e08-438f-4d20-a8c6-7574b4f422e3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermPurchaseCommitmentAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_us-gaap_LongTermPurchaseCommitmentAmount_b7199e08-438f-4d20-a8c6-7574b4f422e3" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_LongTermPurchaseCommitmentRenewalTerm_d8044bfe-884f-47bf-a4cd-4d9a078b907b" xlink:href="sndk-20251003.xsd#sndk_LongTermPurchaseCommitmentRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_sndk_LongTermPurchaseCommitmentRenewalTerm_d8044bfe-884f-47bf-a4cd-4d9a078b907b" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_LongTermPurchaseCommitmentPurchases_29481cb7-a05b-4621-a36a-64fffaf97206" xlink:href="sndk-20251003.xsd#sndk_LongTermPurchaseCommitmentPurchases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_sndk_LongTermPurchaseCommitmentPurchases_29481cb7-a05b-4621-a36a-64fffaf97206" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrentAndNoncurrent_3da1a4ea-d2b5-46c6-a007-f7447ca4fe94" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_beb5dd84-54a4-4828-882f-6b4cf38cb173" xlink:to="loc_us-gaap_AccountsPayableCurrentAndNoncurrent_3da1a4ea-d2b5-46c6-a007-f7447ca4fe94" xlink:type="arc" order="17"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesUnisVentureDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesUnisVentureDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesUnisVentureDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_c151d753-07d0-43cc-9d64-50dc572decc3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_07c8e2ca-74c9-4341-b6c8-a82981d8e85a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_c151d753-07d0-43cc-9d64-50dc572decc3" xlink:to="loc_us-gaap_ConcentrationRiskTable_07c8e2ca-74c9-4341-b6c8-a82981d8e85a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_24acb21e-b0dd-4a1b-bcb2-94d007918ccf" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_07c8e2ca-74c9-4341-b6c8-a82981d8e85a" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_24acb21e-b0dd-4a1b-bcb2-94d007918ccf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_24acb21e-b0dd-4a1b-bcb2-94d007918ccf_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_24acb21e-b0dd-4a1b-bcb2-94d007918ccf" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_24acb21e-b0dd-4a1b-bcb2-94d007918ccf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_97205aa1-2318-4ae2-83e9-97661c77caf5" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_24acb21e-b0dd-4a1b-bcb2-94d007918ccf" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_97205aa1-2318-4ae2-83e9-97661c77caf5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_UnisVentureMember_33983cfa-c5d9-4fd5-a178-e92d1f2855e6" xlink:href="sndk-20251003.xsd#sndk_UnisVentureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_97205aa1-2318-4ae2-83e9-97661c77caf5" xlink:to="loc_sndk_UnisVentureMember_33983cfa-c5d9-4fd5-a178-e92d1f2855e6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_488843ad-1a77-4447-99fd-ed1d212319fc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_07c8e2ca-74c9-4341-b6c8-a82981d8e85a" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_488843ad-1a77-4447-99fd-ed1d212319fc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_488843ad-1a77-4447-99fd-ed1d212319fc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_488843ad-1a77-4447-99fd-ed1d212319fc" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_488843ad-1a77-4447-99fd-ed1d212319fc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_aca3c1cf-2b21-405c-a49e-8759fea9157c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_488843ad-1a77-4447-99fd-ed1d212319fc" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_aca3c1cf-2b21-405c-a49e-8759fea9157c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerMember_9bd69782-c128-472e-b6bb-c5e78cd68bee" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_aca3c1cf-2b21-405c-a49e-8759fea9157c" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerMember_9bd69782-c128-472e-b6bb-c5e78cd68bee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_b1b02f07-03bf-4412-9fe1-4f90b70579ef" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_aca3c1cf-2b21-405c-a49e-8759fea9157c" xlink:to="loc_us-gaap_AccountsReceivableMember_b1b02f07-03bf-4412-9fe1-4f90b70579ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_b4746047-e385-4033-83a7-3b947d62db0d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_07c8e2ca-74c9-4341-b6c8-a82981d8e85a" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_b4746047-e385-4033-83a7-3b947d62db0d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_b4746047-e385-4033-83a7-3b947d62db0d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_b4746047-e385-4033-83a7-3b947d62db0d" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_b4746047-e385-4033-83a7-3b947d62db0d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_62eb4669-3b0f-4eff-8d2e-27990a59f757" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_b4746047-e385-4033-83a7-3b947d62db0d" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_62eb4669-3b0f-4eff-8d2e-27990a59f757" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductConcentrationRiskMember_1e7a8751-97c0-4590-8dae-9a2694e0b59a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProductConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_62eb4669-3b0f-4eff-8d2e-27990a59f757" xlink:to="loc_us-gaap_ProductConcentrationRiskMember_1e7a8751-97c0-4590-8dae-9a2694e0b59a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_4924f71e-02ce-4172-af81-b4f646015ff4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_62eb4669-3b0f-4eff-8d2e-27990a59f757" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_4924f71e-02ce-4172-af81-b4f646015ff4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_038dd2e7-9e3a-4fca-a354-a99f8e04c3eb" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_07c8e2ca-74c9-4341-b6c8-a82981d8e85a" xlink:to="loc_srt_MajorCustomersAxis_038dd2e7-9e3a-4fca-a354-a99f8e04c3eb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_038dd2e7-9e3a-4fca-a354-a99f8e04c3eb_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_038dd2e7-9e3a-4fca-a354-a99f8e04c3eb" xlink:to="loc_srt_NameOfMajorCustomerDomain_038dd2e7-9e3a-4fca-a354-a99f8e04c3eb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_c1eccb28-46df-43fa-a63a-5d4cb8f9cd1d" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_038dd2e7-9e3a-4fca-a354-a99f8e04c3eb" xlink:to="loc_srt_NameOfMajorCustomerDomain_c1eccb28-46df-43fa-a63a-5d4cb8f9cd1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_UnisVentureMember_86b82c68-1e3d-43a6-9179-0128a9055f7a" xlink:href="sndk-20251003.xsd#sndk_UnisVentureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_c1eccb28-46df-43fa-a63a-5d4cb8f9cd1d" xlink:to="loc_sndk_UnisVentureMember_86b82c68-1e3d-43a6-9179-0128a9055f7a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_5f09f9f4-fffd-42be-977e-4bbff10abba2" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_07c8e2ca-74c9-4341-b6c8-a82981d8e85a" xlink:to="loc_dei_LegalEntityAxis_5f09f9f4-fffd-42be-977e-4bbff10abba2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_5f09f9f4-fffd-42be-977e-4bbff10abba2_default" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_5f09f9f4-fffd-42be-977e-4bbff10abba2" xlink:to="loc_dei_EntityDomain_5f09f9f4-fffd-42be-977e-4bbff10abba2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_ccee8890-70dc-4435-bb3d-2e17c8282bff" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_5f09f9f4-fffd-42be-977e-4bbff10abba2" xlink:to="loc_dei_EntityDomain_ccee8890-70dc-4435-bb3d-2e17c8282bff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_UnissoftWuxiGroupCoLtd.Member_11a756f3-010d-4b51-8bec-e053bc1f93ae" xlink:href="sndk-20251003.xsd#sndk_UnissoftWuxiGroupCoLtd.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_ccee8890-70dc-4435-bb3d-2e17c8282bff" xlink:to="loc_sndk_UnissoftWuxiGroupCoLtd.Member_11a756f3-010d-4b51-8bec-e053bc1f93ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_dc54725c-ad26-4d11-a908-b090f2bd5f56" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_c151d753-07d0-43cc-9d64-50dc572decc3" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_dc54725c-ad26-4d11-a908-b090f2bd5f56" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_57c6eb4d-a230-44fe-88ec-8d874ed5d7bb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_c151d753-07d0-43cc-9d64-50dc572decc3" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_57c6eb4d-a230-44fe-88ec-8d874ed5d7bb" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesCombinedConsolidatedIncomeStatementDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesCombinedConsolidatedIncomeStatementDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesCombinedConsolidatedIncomeStatementDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_87c8f9c3-6bd5-4ec2-9d35-eb08c52cd1fc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_c0127477-2dee-4810-9c15-5036e333cbdc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_87c8f9c3-6bd5-4ec2-9d35-eb08c52cd1fc" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_c0127477-2dee-4810-9c15-5036e333cbdc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_97a74718-4b36-48bc-be96-47b2ad82c302" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_c0127477-2dee-4810-9c15-5036e333cbdc" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_97a74718-4b36-48bc-be96-47b2ad82c302" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_97a74718-4b36-48bc-be96-47b2ad82c302_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_97a74718-4b36-48bc-be96-47b2ad82c302" xlink:to="loc_us-gaap_RelatedPartyDomain_97a74718-4b36-48bc-be96-47b2ad82c302_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_9a669483-1063-4690-8866-6bfededd6f40" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_97a74718-4b36-48bc-be96-47b2ad82c302" xlink:to="loc_us-gaap_RelatedPartyDomain_9a669483-1063-4690-8866-6bfededd6f40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_3b4a98ce-9fde-4146-a509-fe874c1dc79b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_9a669483-1063-4690-8866-6bfededd6f40" xlink:to="loc_us-gaap_RelatedPartyMember_3b4a98ce-9fde-4146-a509-fe874c1dc79b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_6db8cef0-52c1-49e5-b59f-24f1f9c60f32" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_87c8f9c3-6bd5-4ec2-9d35-eb08c52cd1fc" xlink:to="loc_us-gaap_InterestExpenseNonoperating_6db8cef0-52c1-49e5-b59f-24f1f9c60f32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_36da447b-7b99-483a-bf75-3a774c3ea2e8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_87c8f9c3-6bd5-4ec2-9d35-eb08c52cd1fc" xlink:to="loc_us-gaap_InvestmentIncomeInterest_36da447b-7b99-483a-bf75-3a774c3ea2e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_301de14c-a3dd-4ff0-b45c-ba83fd7eb13d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_87c8f9c3-6bd5-4ec2-9d35-eb08c52cd1fc" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_301de14c-a3dd-4ff0-b45c-ba83fd7eb13d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_95cc0fa1-d289-4274-b0e4-6d1f4224b28f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_87c8f9c3-6bd5-4ec2-9d35-eb08c52cd1fc" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_95cc0fa1-d289-4274-b0e4-6d1f4224b28f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_BusinessSeparationCosts_3da6dc98-6196-4b83-b2e6-3890f133c486" xlink:href="sndk-20251003.xsd#sndk_BusinessSeparationCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_87c8f9c3-6bd5-4ec2-9d35-eb08c52cd1fc" xlink:to="loc_sndk_BusinessSeparationCosts_3da6dc98-6196-4b83-b2e6-3890f133c486" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_9a3e4c1d-e307-4e0d-b8d8-22d601360388" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_87c8f9c3-6bd5-4ec2-9d35-eb08c52cd1fc" xlink:to="loc_us-gaap_RestructuringCharges_9a3e4c1d-e307-4e0d-b8d8-22d601360388" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_131d6132-e982-49d4-8bfe-8cb55a5e0e28" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_87c8f9c3-6bd5-4ec2-9d35-eb08c52cd1fc" xlink:to="loc_us-gaap_OperatingExpenses_131d6132-e982-49d4-8bfe-8cb55a5e0e28" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesNetTransferFromtoParentDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#RelatedPartiesandRelatedCommitmentsandContingenciesNetTransferFromtoParentDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/RelatedPartiesandRelatedCommitmentsandContingenciesNetTransferFromtoParentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_4eefd514-84d6-4537-b44e-81be6057fb4a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_9cad1c0f-0185-45dd-bb5c-4fe862d7bb89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_4eefd514-84d6-4537-b44e-81be6057fb4a" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_9cad1c0f-0185-45dd-bb5c-4fe862d7bb89" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_acb20681-5126-4b88-8546-89d3bd6ee24c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_9cad1c0f-0185-45dd-bb5c-4fe862d7bb89" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_acb20681-5126-4b88-8546-89d3bd6ee24c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_acb20681-5126-4b88-8546-89d3bd6ee24c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_acb20681-5126-4b88-8546-89d3bd6ee24c" xlink:to="loc_us-gaap_RelatedPartyDomain_acb20681-5126-4b88-8546-89d3bd6ee24c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_f6f886a5-39fc-462e-85e0-cc9cfd6caeef" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_acb20681-5126-4b88-8546-89d3bd6ee24c" xlink:to="loc_us-gaap_RelatedPartyDomain_f6f886a5-39fc-462e-85e0-cc9cfd6caeef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_54d2fbca-ccc8-4a93-ac3f-4e9432df4475" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_f6f886a5-39fc-462e-85e0-cc9cfd6caeef" xlink:to="loc_us-gaap_RelatedPartyMember_54d2fbca-ccc8-4a93-ac3f-4e9432df4475" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_TransfersInTransfersOutFromParentStockholdersEquity_440afc73-75df-4902-8f8e-8d6628d86219" xlink:href="sndk-20251003.xsd#sndk_TransfersInTransfersOutFromParentStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_4eefd514-84d6-4537-b44e-81be6057fb4a" xlink:to="loc_sndk_TransfersInTransfersOutFromParentStockholdersEquity_440afc73-75df-4902-8f8e-8d6628d86219" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_OtherSignificantNoncashTransactionTransferOfNotesReceivableToParent_22a2a71d-04c5-4f70-94ca-7d4c68346e61" xlink:href="sndk-20251003.xsd#sndk_OtherSignificantNoncashTransactionTransferOfNotesReceivableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_4eefd514-84d6-4537-b44e-81be6057fb4a" xlink:to="loc_sndk_OtherSignificantNoncashTransactionTransferOfNotesReceivableToParent_22a2a71d-04c5-4f70-94ca-7d4c68346e61" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_OtherSignificantNoncashTransactionTransferOfChangesInOtherAssetsLiabilitiesFromParent_80b065c5-09ad-46d8-b93c-4faa1e6c4ee7" xlink:href="sndk-20251003.xsd#sndk_OtherSignificantNoncashTransactionTransferOfChangesInOtherAssetsLiabilitiesFromParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_4eefd514-84d6-4537-b44e-81be6057fb4a" xlink:to="loc_sndk_OtherSignificantNoncashTransactionTransferOfChangesInOtherAssetsLiabilitiesFromParent_80b065c5-09ad-46d8-b93c-4faa1e6c4ee7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_OtherSignificantNoncashTransactionTransferOfPropertyPlantAndEquipmentFromParent_4ed93dce-dfef-42af-8711-6838e092789d" xlink:href="sndk-20251003.xsd#sndk_OtherSignificantNoncashTransactionTransferOfPropertyPlantAndEquipmentFromParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_4eefd514-84d6-4537-b44e-81be6057fb4a" xlink:to="loc_sndk_OtherSignificantNoncashTransactionTransferOfPropertyPlantAndEquipmentFromParent_4ed93dce-dfef-42af-8711-6838e092789d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_OtherSignificantNoncashTransactionTransferOfDeferredTaxAssetsFromParent_c8df87e1-19cb-48e7-acff-5955c41df5da" xlink:href="sndk-20251003.xsd#sndk_OtherSignificantNoncashTransactionTransferOfDeferredTaxAssetsFromParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_4eefd514-84d6-4537-b44e-81be6057fb4a" xlink:to="loc_sndk_OtherSignificantNoncashTransactionTransferOfDeferredTaxAssetsFromParent_c8df87e1-19cb-48e7-acff-5955c41df5da" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_NetTransfersFromToParentPerCondensedCombinedStatementsOfCashFlows_2ffb99d8-ae34-46d9-8c90-d40dc4ddf670" xlink:href="sndk-20251003.xsd#sndk_NetTransfersFromToParentPerCondensedCombinedStatementsOfCashFlows"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_4eefd514-84d6-4537-b44e-81be6057fb4a" xlink:to="loc_sndk_NetTransfersFromToParentPerCondensedCombinedStatementsOfCashFlows_2ffb99d8-ae34-46d9-8c90-d40dc4ddf670" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/ShareholdersEquityAdditionalInformationDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#ShareholdersEquityAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/ShareholdersEquityAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_52f8de1f-1755-4059-9bce-085bd22686c3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_486cd27e-29f5-4ffc-acc5-fc596e234db1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_52f8de1f-1755-4059-9bce-085bd22686c3" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_486cd27e-29f5-4ffc-acc5-fc596e234db1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_ac723883-98ab-4a71-b56d-bece47a9fdce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_486cd27e-29f5-4ffc-acc5-fc596e234db1" xlink:to="loc_us-gaap_AwardTypeAxis_ac723883-98ab-4a71-b56d-bece47a9fdce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ac723883-98ab-4a71-b56d-bece47a9fdce_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_ac723883-98ab-4a71-b56d-bece47a9fdce" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ac723883-98ab-4a71-b56d-bece47a9fdce_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b131a6df-d8e8-4179-8954-19754fa98909" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_ac723883-98ab-4a71-b56d-bece47a9fdce" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b131a6df-d8e8-4179-8954-19754fa98909" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_6bf9a1a0-c3af-460f-b78e-5fc2f7d3587b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b131a6df-d8e8-4179-8954-19754fa98909" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_6bf9a1a0-c3af-460f-b78e-5fc2f7d3587b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_af48e2d1-ab71-4658-983e-4126837b577d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b131a6df-d8e8-4179-8954-19754fa98909" xlink:to="loc_us-gaap_PerformanceSharesMember_af48e2d1-ab71-4658-983e-4126837b577d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_60685971-0cbf-4d0d-aa52-370d53e4bde7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b131a6df-d8e8-4179-8954-19754fa98909" xlink:to="loc_us-gaap_EmployeeStockMember_60685971-0cbf-4d0d-aa52-370d53e4bde7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_87fde011-2952-4c87-bc41-0d62e3926262" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_486cd27e-29f5-4ffc-acc5-fc596e234db1" xlink:to="loc_srt_RangeAxis_87fde011-2952-4c87-bc41-0d62e3926262" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_87fde011-2952-4c87-bc41-0d62e3926262_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_87fde011-2952-4c87-bc41-0d62e3926262" xlink:to="loc_srt_RangeMember_87fde011-2952-4c87-bc41-0d62e3926262_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2d71e956-e09d-4574-a6d5-cc0806675b2f" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_87fde011-2952-4c87-bc41-0d62e3926262" xlink:to="loc_srt_RangeMember_2d71e956-e09d-4574-a6d5-cc0806675b2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_4901b8f7-a9cb-4968-b7dd-9916a7521c0a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2d71e956-e09d-4574-a6d5-cc0806675b2f" xlink:to="loc_srt_MinimumMember_4901b8f7-a9cb-4968-b7dd-9916a7521c0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_0e67eefa-e2c3-4f63-96ed-c52439b5f65c" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2d71e956-e09d-4574-a6d5-cc0806675b2f" xlink:to="loc_srt_MaximumMember_0e67eefa-e2c3-4f63-96ed-c52439b5f65c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_ShareBasedPaymentArrangementPlanModificationExpectedIncrementalCost_03b5584a-c267-47ae-90c7-e8f75299bf1a" xlink:href="sndk-20251003.xsd#sndk_ShareBasedPaymentArrangementPlanModificationExpectedIncrementalCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_52f8de1f-1755-4059-9bce-085bd22686c3" xlink:to="loc_sndk_ShareBasedPaymentArrangementPlanModificationExpectedIncrementalCost_03b5584a-c267-47ae-90c7-e8f75299bf1a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationIncrementalCompensationCost_bf8c1fc6-326d-4515-8da2-bb32658d06f5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationIncrementalCompensationCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_52f8de1f-1755-4059-9bce-085bd22686c3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationIncrementalCompensationCost_bf8c1fc6-326d-4515-8da2-bb32658d06f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_ShareBasedPaymentArrangementPlanModificationIncrementalCostRemainingCost_184382a5-7f1f-4054-9184-2a1ebd8d62bb" xlink:href="sndk-20251003.xsd#sndk_ShareBasedPaymentArrangementPlanModificationIncrementalCostRemainingCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_52f8de1f-1755-4059-9bce-085bd22686c3" xlink:to="loc_sndk_ShareBasedPaymentArrangementPlanModificationIncrementalCostRemainingCost_184382a5-7f1f-4054-9184-2a1ebd8d62bb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_f8c94e22-8e54-493d-b9a3-9de8ae1800e9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_52f8de1f-1755-4059-9bce-085bd22686c3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_f8c94e22-8e54-493d-b9a3-9de8ae1800e9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_119ef80c-112b-48bc-877b-bf845d073722" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_52f8de1f-1755-4059-9bce-085bd22686c3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_119ef80c-112b-48bc-877b-bf845d073722" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_ShareBasedCompensationArrangementByShareBasedPaymentTargetPerformancePercentage_f480cf2d-c947-4deb-b88a-410313c9dfc8" xlink:href="sndk-20251003.xsd#sndk_ShareBasedCompensationArrangementByShareBasedPaymentTargetPerformancePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_52f8de1f-1755-4059-9bce-085bd22686c3" xlink:to="loc_sndk_ShareBasedCompensationArrangementByShareBasedPaymentTargetPerformancePercentage_f480cf2d-c947-4deb-b88a-410313c9dfc8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_8b03dbdd-bb51-44d2-9779-00c331b542c2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_52f8de1f-1755-4059-9bce-085bd22686c3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_8b03dbdd-bb51-44d2-9779-00c331b542c2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_ad613aea-e4ea-4570-bd33-0587b95aaac1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_52f8de1f-1755-4059-9bce-085bd22686c3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_ad613aea-e4ea-4570-bd33-0587b95aaac1" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_cc84455f-b40c-48ef-a461-32b4911f2d98" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_52f8de1f-1755-4059-9bce-085bd22686c3" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_cc84455f-b40c-48ef-a461-32b4911f2d98" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/ShareholdersEquityAwardActivityDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#ShareholdersEquityAwardActivityDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/ShareholdersEquityAwardActivityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ebcdcf26-02d4-480e-811d-c99ce52cd453" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0e0cde15-cff9-4f75-82d7-a5251b2a60da" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ebcdcf26-02d4-480e-811d-c99ce52cd453" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0e0cde15-cff9-4f75-82d7-a5251b2a60da" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_96366830-a603-4ac2-87f7-8348ecd1e892" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0e0cde15-cff9-4f75-82d7-a5251b2a60da" xlink:to="loc_us-gaap_AwardTypeAxis_96366830-a603-4ac2-87f7-8348ecd1e892" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_96366830-a603-4ac2-87f7-8348ecd1e892_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_96366830-a603-4ac2-87f7-8348ecd1e892" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_96366830-a603-4ac2-87f7-8348ecd1e892_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_566ba267-28dd-4194-b3ca-02afc21b72e6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_96366830-a603-4ac2-87f7-8348ecd1e892" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_566ba267-28dd-4194-b3ca-02afc21b72e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_RestrictedStockUnitsAndPerformanceShareUnitsMember_2e1cc6ce-e4e9-440e-b6d8-31015edfa7ff" xlink:href="sndk-20251003.xsd#sndk_RestrictedStockUnitsAndPerformanceShareUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_566ba267-28dd-4194-b3ca-02afc21b72e6" xlink:to="loc_sndk_RestrictedStockUnitsAndPerformanceShareUnitsMember_2e1cc6ce-e4e9-440e-b6d8-31015edfa7ff" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_478201a1-f0d9-4638-a3ac-a69dcaae33e6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ebcdcf26-02d4-480e-811d-c99ce52cd453" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_478201a1-f0d9-4638-a3ac-a69dcaae33e6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_304f8222-5b8a-489f-8b38-a86f346134ff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_478201a1-f0d9-4638-a3ac-a69dcaae33e6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_304f8222-5b8a-489f-8b38-a86f346134ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_59cabe92-ec5f-4313-a67b-7217a38c47bf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_478201a1-f0d9-4638-a3ac-a69dcaae33e6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_59cabe92-ec5f-4313-a67b-7217a38c47bf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_01b988df-b190-4051-adf9-9a1984bb2636" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_478201a1-f0d9-4638-a3ac-a69dcaae33e6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_01b988df-b190-4051-adf9-9a1984bb2636" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_dec0d1ce-2876-43ff-916e-b19eeb855651" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_478201a1-f0d9-4638-a3ac-a69dcaae33e6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_dec0d1ce-2876-43ff-916e-b19eeb855651" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_777a1c22-de45-4ada-9c49-94457f2e29d7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_f869c4ac-7ca0-4534-a2e8-cb6bd61859de" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ebcdcf26-02d4-480e-811d-c99ce52cd453" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_f869c4ac-7ca0-4534-a2e8-cb6bd61859de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_4c03a2f8-0a77-451c-884c-e51bbb147f52" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_f869c4ac-7ca0-4534-a2e8-cb6bd61859de" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_4c03a2f8-0a77-451c-884c-e51bbb147f52" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_dbb47162-6aa3-4700-b42f-a426c2494306" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_f869c4ac-7ca0-4534-a2e8-cb6bd61859de" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_dbb47162-6aa3-4700-b42f-a426c2494306" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_c5567e39-5825-45c6-9869-7fae37472bda" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_f869c4ac-7ca0-4534-a2e8-cb6bd61859de" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_c5567e39-5825-45c6-9869-7fae37472bda" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_546d05d9-2507-4d9b-b72b-1cbdf9529013" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_f869c4ac-7ca0-4534-a2e8-cb6bd61859de" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_546d05d9-2507-4d9b-b72b-1cbdf9529013" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_a598a387-379a-4838-a09a-b455116524c5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_afc57eff-2adc-4e96-93be-e766270e76a7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ebcdcf26-02d4-480e-811d-c99ce52cd453" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_afc57eff-2adc-4e96-93be-e766270e76a7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValue_86c1ce9c-722e-4b5e-8ff0-820138d505e4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_afc57eff-2adc-4e96-93be-e766270e76a7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValue_86c1ce9c-722e-4b5e-8ff0-820138d505e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodIntrinsicValue_4dd26bbc-acaf-48dc-8d27-b935da72116c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_afc57eff-2adc-4e96-93be-e766270e76a7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodIntrinsicValue_4dd26bbc-acaf-48dc-8d27-b935da72116c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodIntrinsicValue_78696b40-9689-42ce-9257-cd048f7db18e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_afc57eff-2adc-4e96-93be-e766270e76a7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodIntrinsicValue_78696b40-9689-42ce-9257-cd048f7db18e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresIntrinsicValue_ffced714-912d-43c4-8851-3ee941fe1498" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_afc57eff-2adc-4e96-93be-e766270e76a7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresIntrinsicValue_ffced714-912d-43c4-8851-3ee941fe1498" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValue_5ddd0014-f364-43fd-88cb-919291c3d37b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValue"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/ShareholdersEquityUnamortizedCompensationCostsDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#ShareholdersEquityUnamortizedCompensationCostsDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/ShareholdersEquityUnamortizedCompensationCostsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_db7bc1a0-9a9f-4003-85ee-164a335b4bdd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_70d1f7b7-e891-4a35-b225-2f018b192517" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_db7bc1a0-9a9f-4003-85ee-164a335b4bdd" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_70d1f7b7-e891-4a35-b225-2f018b192517" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_070487a4-219f-4afb-9226-161c4e3045cf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_70d1f7b7-e891-4a35-b225-2f018b192517" xlink:to="loc_us-gaap_AwardTypeAxis_070487a4-219f-4afb-9226-161c4e3045cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_070487a4-219f-4afb-9226-161c4e3045cf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_070487a4-219f-4afb-9226-161c4e3045cf" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_070487a4-219f-4afb-9226-161c4e3045cf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9d7408e3-ca22-4f4e-90c3-caafa9f88ed9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_070487a4-219f-4afb-9226-161c4e3045cf" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9d7408e3-ca22-4f4e-90c3-caafa9f88ed9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_RestrictedStockUnitsAndPerformanceShareUnitsMember_8055fa1f-bcb7-498b-8ad1-f57e35a8193c" xlink:href="sndk-20251003.xsd#sndk_RestrictedStockUnitsAndPerformanceShareUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9d7408e3-ca22-4f4e-90c3-caafa9f88ed9" xlink:to="loc_sndk_RestrictedStockUnitsAndPerformanceShareUnitsMember_8055fa1f-bcb7-498b-8ad1-f57e35a8193c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_dbc20196-4062-4ada-a5a0-d29893ab57fb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9d7408e3-ca22-4f4e-90c3-caafa9f88ed9" xlink:to="loc_us-gaap_EmployeeStockMember_dbc20196-4062-4ada-a5a0-d29893ab57fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_307e112f-55a4-4dc8-8d3c-4a529950587a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_db7bc1a0-9a9f-4003-85ee-164a335b4bdd" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_307e112f-55a4-4dc8-8d3c-4a529950587a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_72be2fdb-9db0-497f-a0e5-c5c9a303b0da" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_db7bc1a0-9a9f-4003-85ee-164a335b4bdd" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_72be2fdb-9db0-497f-a0e5-c5c9a303b0da" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/ShareholdersEquityScheduleofStockBasedCompensationExpenseDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#ShareholdersEquityScheduleofStockBasedCompensationExpenseDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/ShareholdersEquityScheduleofStockBasedCompensationExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e2f6cbe0-3369-49f3-b09f-21536cd0f730" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a75be5d6-31fb-4a7a-be02-e092200b55a8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e2f6cbe0-3369-49f3-b09f-21536cd0f730" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a75be5d6-31fb-4a7a-be02-e092200b55a8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_3a3dcea2-e61d-4342-94b2-f3caf719387b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a75be5d6-31fb-4a7a-be02-e092200b55a8" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_3a3dcea2-e61d-4342-94b2-f3caf719387b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_3a3dcea2-e61d-4342-94b2-f3caf719387b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_3a3dcea2-e61d-4342-94b2-f3caf719387b" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_3a3dcea2-e61d-4342-94b2-f3caf719387b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_c6a847b5-3548-4a72-a4b4-a6e0503de813" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_3a3dcea2-e61d-4342-94b2-f3caf719387b" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_c6a847b5-3548-4a72-a4b4-a6e0503de813" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_06b383a2-0978-4128-9234-bd0c0de38d71" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_c6a847b5-3548-4a72-a4b4-a6e0503de813" xlink:to="loc_us-gaap_CostOfSalesMember_06b383a2-0978-4128-9234-bd0c0de38d71" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_f8971a1e-b7d0-4cb5-800b-4f05727afe76" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_c6a847b5-3548-4a72-a4b4-a6e0503de813" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_f8971a1e-b7d0-4cb5-800b-4f05727afe76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_087ca3f7-e185-4825-9af6-371524aa441a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_c6a847b5-3548-4a72-a4b4-a6e0503de813" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_087ca3f7-e185-4825-9af6-371524aa441a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_70a66112-c171-41a5-9f0e-fece5d007a44" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a75be5d6-31fb-4a7a-be02-e092200b55a8" xlink:to="loc_us-gaap_AwardTypeAxis_70a66112-c171-41a5-9f0e-fece5d007a44" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_70a66112-c171-41a5-9f0e-fece5d007a44_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_70a66112-c171-41a5-9f0e-fece5d007a44" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_70a66112-c171-41a5-9f0e-fece5d007a44_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c5d98102-95f3-4d28-8c73-dc958eb3f07a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_70a66112-c171-41a5-9f0e-fece5d007a44" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c5d98102-95f3-4d28-8c73-dc958eb3f07a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_RestrictedStockUnitsAndPerformanceShareUnitsMember_f219246a-0e61-43e0-ba99-3c13de435aa5" xlink:href="sndk-20251003.xsd#sndk_RestrictedStockUnitsAndPerformanceShareUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c5d98102-95f3-4d28-8c73-dc958eb3f07a" xlink:to="loc_sndk_RestrictedStockUnitsAndPerformanceShareUnitsMember_f219246a-0e61-43e0-ba99-3c13de435aa5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_8a7662ba-305b-4f95-a959-afce3637418b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c5d98102-95f3-4d28-8c73-dc958eb3f07a" xlink:to="loc_us-gaap_EmployeeStockMember_8a7662ba-305b-4f95-a959-afce3637418b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_815e6d29-ce99-4621-821f-bd9cb00f005e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e2f6cbe0-3369-49f3-b09f-21536cd0f730" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_815e6d29-ce99-4621-821f-bd9cb00f005e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_2ebb0ae2-73d3-499c-a6b4-f1599934b422" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e2f6cbe0-3369-49f3-b09f-21536cd0f730" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_2ebb0ae2-73d3-499c-a6b4-f1599934b422" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax_bc60994d-cf2e-43ac-8ab6-a1ec93c44b16" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e2f6cbe0-3369-49f3-b09f-21536cd0f730" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax_bc60994d-cf2e-43ac-8ab6-a1ec93c44b16" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sandisk.com/role/NetIncomeperCommonShareDetails" xlink:type="simple" xlink:href="sndk-20251003.xsd#NetIncomeperCommonShareDetails"/>
  <link:definitionLink xlink:role="http://www.sandisk.com/role/NetIncomeperCommonShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasicLineItems_dbaf66d9-4c75-40e9-84fc-5119ad1f42ec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareBasicLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable_dc5daaa1-046b-4f86-92e6-dcdca107fadb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_dbaf66d9-4c75-40e9-84fc-5119ad1f42ec" xlink:to="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable_dc5daaa1-046b-4f86-92e6-dcdca107fadb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_5dc355b6-3e8f-46f0-8f5a-27e6c44314df" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable_dc5daaa1-046b-4f86-92e6-dcdca107fadb" xlink:to="loc_dei_LegalEntityAxis_5dc355b6-3e8f-46f0-8f5a-27e6c44314df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_5dc355b6-3e8f-46f0-8f5a-27e6c44314df_default" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_5dc355b6-3e8f-46f0-8f5a-27e6c44314df" xlink:to="loc_dei_EntityDomain_5dc355b6-3e8f-46f0-8f5a-27e6c44314df_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_904f402b-5de8-49da-aa17-c0dffccacee7" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_5dc355b6-3e8f-46f0-8f5a-27e6c44314df" xlink:to="loc_dei_EntityDomain_904f402b-5de8-49da-aa17-c0dffccacee7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_WesternDigitalCorporationMember_a4df49da-2d63-470b-8faf-07f93e57b56a" xlink:href="sndk-20251003.xsd#sndk_WesternDigitalCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_904f402b-5de8-49da-aa17-c0dffccacee7" xlink:to="loc_sndk_WesternDigitalCorporationMember_a4df49da-2d63-470b-8faf-07f93e57b56a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sndk_SpinOffTransactionProRataDistributionOutstandingSharesPercentage_ef03918c-9adf-4089-b1af-a9b8e29a58cc" xlink:href="sndk-20251003.xsd#sndk_SpinOffTransactionProRataDistributionOutstandingSharesPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_dbaf66d9-4c75-40e9-84fc-5119ad1f42ec" xlink:to="loc_sndk_SpinOffTransactionProRataDistributionOutstandingSharesPercentage_ef03918c-9adf-4089-b1af-a9b8e29a58cc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_f762dda1-a99d-452d-bb00-3484835129a1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_dbaf66d9-4c75-40e9-84fc-5119ad1f42ec" xlink:to="loc_us-gaap_CommonStockSharesIssued_f762dda1-a99d-452d-bb00-3484835129a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_7f8b2cdc-3f1d-42b6-ad62-238a8cef8210" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_dbaf66d9-4c75-40e9-84fc-5119ad1f42ec" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_7f8b2cdc-3f1d-42b6-ad62-238a8cef8210" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_1988e390-c3ea-4632-8f89-621cc8e92903" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_dbaf66d9-4c75-40e9-84fc-5119ad1f42ec" xlink:to="loc_us-gaap_NetIncomeLoss_1988e390-c3ea-4632-8f89-621cc8e92903" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_bca976b5-86e3-42f6-8b7a-87239f05d163" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_dbaf66d9-4c75-40e9-84fc-5119ad1f42ec" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_bca976b5-86e3-42f6-8b7a-87239f05d163" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_8724125f-ef10-4377-9cef-1e88dc4999ba" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_bca976b5-86e3-42f6-8b7a-87239f05d163" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_8724125f-ef10-4377-9cef-1e88dc4999ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_f5986489-0307-4230-bb32-d34b54d11123" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_bca976b5-86e3-42f6-8b7a-87239f05d163" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_f5986489-0307-4230-bb32-d34b54d11123" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareReconciliationAbstract_e6ac482c-9d79-497f-b452-82abf70b3714" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareReconciliationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_dbaf66d9-4c75-40e9-84fc-5119ad1f42ec" xlink:to="loc_us-gaap_EarningsPerShareReconciliationAbstract_e6ac482c-9d79-497f-b452-82abf70b3714" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_3f9e5e98-61f6-45c1-afee-b4679944b7f0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareReconciliationAbstract_e6ac482c-9d79-497f-b452-82abf70b3714" xlink:to="loc_us-gaap_EarningsPerShareBasic_3f9e5e98-61f6-45c1-afee-b4679944b7f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_d9131094-2a9f-4298-a445-55c0547e056f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareReconciliationAbstract_e6ac482c-9d79-497f-b452-82abf70b3714" xlink:to="loc_us-gaap_EarningsPerShareDiluted_d9131094-2a9f-4298-a445-55c0547e056f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_84fafd7d-2ad2-466c-ad5d-703f422d6222" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems_dbaf66d9-4c75-40e9-84fc-5119ad1f42ec" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_84fafd7d-2ad2-466c-ad5d-703f422d6222" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-roles-2025.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_OtherAssetsNoncurrent" xlink:type="arc" order="101"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:type="arc" order="41"/>
  </link:definitionLink>
</link:linkbase>
