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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:01a0399f-a9a3-7223-9c1c-40f7484b36f3,g:d3a7a231-2c6f-4001-bf73-73ca5f937ee5-->
<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://curiositystream.com/role/DocumentandEntityInformation" xlink:type="simple" xlink:href="curi-20260826.xsd#DocumentandEntityInformation"/>
  <link:definitionLink xlink:role="http://curiositystream.com/role/DocumentandEntityInformation" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_01a0399f-a9a3-7696-9cdc-0c721595cf67" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentInformationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_DocumentInformationTable_01a0399f-a9a3-7696-9cdc-0c721595cf67" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_01a0399f-a9a3-710f-b01a-e71fdf509a56" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_01a0399f-a9a3-7696-9cdc-0c721595cf67" xlink:to="loc_us-gaap_StatementClassOfStockAxis_01a0399f-a9a3-710f-b01a-e71fdf509a56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a0399f-a9a3-710f-b01a-e71fdf509a56_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_01a0399f-a9a3-710f-b01a-e71fdf509a56" xlink:to="loc_us-gaap_ClassOfStockDomain_01a0399f-a9a3-710f-b01a-e71fdf509a56_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a0399f-a9a3-70fc-8d22-785db6c91c1e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_01a0399f-a9a3-710f-b01a-e71fdf509a56" xlink:to="loc_us-gaap_ClassOfStockDomain_01a0399f-a9a3-70fc-8d22-785db6c91c1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_curi_CommonStockParValue00001Member_01a0399f-a9a3-7f4f-97e6-b70e01be3c96" xlink:href="curi-20260826.xsd#curi_CommonStockParValue00001Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a0399f-a9a3-70fc-8d22-785db6c91c1e" xlink:to="loc_curi_CommonStockParValue00001Member_01a0399f-a9a3-7f4f-97e6-b70e01be3c96" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_curi_WarrantsEachExercisableForOneShareOfCommonStockAtAnExercisePriceOf1150PerShare1Member_01a0399f-a9a3-74ec-994c-0dd83225b9a7" xlink:href="curi-20260826.xsd#curi_WarrantsEachExercisableForOneShareOfCommonStockAtAnExercisePriceOf1150PerShare1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a0399f-a9a3-70fc-8d22-785db6c91c1e" xlink:to="loc_curi_WarrantsEachExercisableForOneShareOfCommonStockAtAnExercisePriceOf1150PerShare1Member_01a0399f-a9a3-74ec-994c-0dd83225b9a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_01a0399f-a9a3-78af-9c6b-bf3623b26b86" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_DocumentType_01a0399f-a9a3-78af-9c6b-bf3623b26b86" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_01a0399f-a9a3-7f62-8b4a-3a7547e97fae" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_DocumentPeriodEndDate_01a0399f-a9a3-7f62-8b4a-3a7547e97fae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_01a0399f-a9a3-74e6-a698-621c22bf4f50" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_EntityRegistrantName_01a0399f-a9a3-74e6-a698-621c22bf4f50" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_01a0399f-a9a3-7457-a3cb-26e65f8e16cb" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_EntityIncorporationStateCountryCode_01a0399f-a9a3-7457-a3cb-26e65f8e16cb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_01a0399f-a9a3-79fc-b544-ac03fb8c5eb6" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_EntityFileNumber_01a0399f-a9a3-79fc-b544-ac03fb8c5eb6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_01a0399f-a9a3-7585-8cfe-a27f7bfaab60" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_EntityTaxIdentificationNumber_01a0399f-a9a3-7585-8cfe-a27f7bfaab60" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_01a0399f-a9a3-7531-9995-8e1417cc04e7" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_EntityAddressAddressLine1_01a0399f-a9a3-7531-9995-8e1417cc04e7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2_01a0399f-a9a3-7bc2-8224-e165a43e555c" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressAddressLine2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_EntityAddressAddressLine2_01a0399f-a9a3-7bc2-8224-e165a43e555c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_01a0399f-a9a3-7cfa-bb36-3281140a021d" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_EntityAddressCityOrTown_01a0399f-a9a3-7cfa-bb36-3281140a021d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_01a0399f-a9a3-7883-a748-de378a69945e" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_EntityAddressStateOrProvince_01a0399f-a9a3-7883-a748-de378a69945e" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_01a0399f-a9a3-7e97-bdbe-ba400fc291c6" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_EntityAddressPostalZipCode_01a0399f-a9a3-7e97-bdbe-ba400fc291c6" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_01a0399f-a9a3-7774-a973-c997eb167a7f" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_CityAreaCode_01a0399f-a9a3-7774-a973-c997eb167a7f" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_01a0399f-a9a3-7534-9214-61103ef3b66c" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_LocalPhoneNumber_01a0399f-a9a3-7534-9214-61103ef3b66c" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_01a0399f-a9a3-7c93-98da-f537f203b4f7" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_WrittenCommunications_01a0399f-a9a3-7c93-98da-f537f203b4f7" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_01a0399f-a9a3-7794-9e1a-f25a2f3c5ae4" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_SolicitingMaterial_01a0399f-a9a3-7794-9e1a-f25a2f3c5ae4" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_01a0399f-a9a3-771a-99f3-111187598a1a" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_PreCommencementTenderOffer_01a0399f-a9a3-771a-99f3-111187598a1a" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_01a0399f-a9a3-7d6f-86d9-ade6e13e40a2" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_01a0399f-a9a3-7d6f-86d9-ade6e13e40a2" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_01a0399f-a9a3-7dd5-a9cd-eda26817e6c2" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_Security12bTitle_01a0399f-a9a3-7dd5-a9cd-eda26817e6c2" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_01a0399f-a9a3-7154-ad7c-d6f273bd6fd3" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_TradingSymbol_01a0399f-a9a3-7154-ad7c-d6f273bd6fd3" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_01a0399f-a9a3-7ecd-b1ff-b453ea26118f" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_SecurityExchangeName_01a0399f-a9a3-7ecd-b1ff-b453ea26118f" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_01a0399f-a9a3-7a67-9cd2-0d404678c0e8" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_EntityEmergingGrowthCompany_01a0399f-a9a3-7a67-9cd2-0d404678c0e8" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityExTransitionPeriod_01a0399f-a9a3-7d67-8c82-167e1a7ca9ca" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityExTransitionPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_EntityExTransitionPeriod_01a0399f-a9a3-7d67-8c82-167e1a7ca9ca" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_01a0399f-a9a3-7f55-afc2-84a79bd4abd5" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_AmendmentFlag_01a0399f-a9a3-7f55-afc2-84a79bd4abd5" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_01a0399f-a9a3-763c-9c95-c75201e417d8" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_EntityCentralIndexKey_01a0399f-a9a3-763c-9c95-c75201e417d8" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_01a0399f-a9a3-7fef-b20d-09d40c19a10e" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_01a0399f-a9a3-75d0-ad16-1aea70fd3495" xlink:to="loc_dei_CurrentFiscalYearEndDate_01a0399f-a9a3-7fef-b20d-09d40c19a10e" xlink:type="arc" order="24"/>
  </link:definitionLink>
</link:linkbase>
