diff --git a/dom/base/Document.cpp b/dom/base/Document.cpp
index 79ba99e7d133..0fe279384312 100644
--- a/dom/base/Document.cpp
+++ b/dom/base/Document.cpp
@@ -16238,7 +16238,7 @@ nsICookieJarSettings* Document::CookieJarSettings() {
                   inProcessParent->CookieJarSettings()->GetCookieBehavior(),
                   mozilla::net::CookieJarSettings::Cast(
                       inProcessParent->CookieJarSettings())
-                      ->GetFirstPartyDomain(),
+                      ->GetPartitionKey(),
                   inProcessParent->CookieJarSettings()
                       ->GetIsFirstPartyIsolated())
             : net::CookieJarSettings::Create();
diff --git a/netwerk/cookie/CookieJarSettings.cpp b/netwerk/cookie/CookieJarSettings.cpp
index b5f7afdef7a3..aa282e397c6b 100644
--- a/netwerk/cookie/CookieJarSettings.cpp
+++ b/netwerk/cookie/CookieJarSettings.cpp
@@ -103,13 +103,13 @@ already_AddRefed<nsICookieJarSettings> CookieJarSettings::Create() {
 
 // static
 already_AddRefed<nsICookieJarSettings> CookieJarSettings::Create(
-    uint32_t aCookieBehavior, const nsAString& aFirstPartyDomain,
+    uint32_t aCookieBehavior, const nsAString& aPartitionKey,
     bool aIsFirstPartyIsolated) {
   MOZ_ASSERT(NS_IsMainThread());
 
   RefPtr<CookieJarSettings> cookieJarSettings = new CookieJarSettings(
       aCookieBehavior, aIsFirstPartyIsolated, eProgressive);
-  cookieJarSettings->mFirstPartyDomain = aFirstPartyDomain;
+  cookieJarSettings->mPartitionKey = aPartitionKey;
 
   return cookieJarSettings.forget();
 }
@@ -196,8 +196,8 @@ CookieJarSettings::GetIsOnContentBlockingAllowList(
 }
 
 NS_IMETHODIMP
-CookieJarSettings::GetFirstPartyDomain(nsAString& aFirstPartyDomain) {
-  aFirstPartyDomain = mFirstPartyDomain;
+CookieJarSettings::GetPartitionKey(nsAString& aPartitionKey) {
+  aPartitionKey = mPartitionKey;
   return NS_OK;
 }
 
@@ -282,7 +282,7 @@ void CookieJarSettings::Serialize(CookieJarSettingsArgs& aData) {
   aData.cookieBehavior() = mCookieBehavior;
   aData.isFirstPartyIsolated() = mIsFirstPartyIsolated;
   aData.isOnContentBlockingAllowList() = mIsOnContentBlockingAllowList;
-  aData.firstPartyDomain() = mFirstPartyDomain;
+  aData.partitionKey() = mPartitionKey;
 
   for (const RefPtr<nsIPermission>& permission : mCookiePermissions) {
     nsCOMPtr<nsIPrincipal> principal;
@@ -342,7 +342,7 @@ void CookieJarSettings::Serialize(CookieJarSettingsArgs& aData) {
   cookieJarSettings->mIsOnContentBlockingAllowList =
       aData.isOnContentBlockingAllowList();
   cookieJarSettings->mCookiePermissions.SwapElements(list);
-  cookieJarSettings->mFirstPartyDomain = aData.firstPartyDomain();
+  cookieJarSettings->mPartitionKey = aData.partitionKey();
 
   cookieJarSettings.forget(aCookieJarSettings);
 }
@@ -411,12 +411,12 @@ void CookieJarSettings::Merge(const CookieJarSettingsArgs& aData) {
   }
 }
 
-void CookieJarSettings::SetFirstPartyDomain(nsIURI* aURI) {
+void CookieJarSettings::SetPartitionKey(nsIURI* aURI) {
   MOZ_ASSERT(aURI);
 
   OriginAttributes attrs;
-  attrs.SetFirstPartyDomain(true, aURI, true);
-  mFirstPartyDomain = std::move(attrs.mFirstPartyDomain);
+  attrs.SetPartitionKey(aURI);
+  mPartitionKey = std::move(attrs.mPartitionKey);
 }
 
 void CookieJarSettings::UpdateIsOnContentBlockingAllowList(
diff --git a/netwerk/cookie/CookieJarSettings.h b/netwerk/cookie/CookieJarSettings.h
index d2615c0b794d..51a0634bf33a 100644
--- a/netwerk/cookie/CookieJarSettings.h
+++ b/netwerk/cookie/CookieJarSettings.h
@@ -117,7 +117,7 @@ class CookieJarSettings final : public nsICookieJarSettings {
   static already_AddRefed<nsICookieJarSettings> Create();
 
   static already_AddRefed<nsICookieJarSettings> Create(
-      uint32_t aCookieBehavior, const nsAString& aFirstPartyDomain,
+      uint32_t aCookieBehavior, const nsAString& aPartitionKey,
       bool aIsFirstPartyIsolated);
 
   static CookieJarSettings* Cast(nsICookieJarSettings* aCS) {
@@ -138,8 +138,8 @@ class CookieJarSettings final : public nsICookieJarSettings {
 
   void UpdateIsOnContentBlockingAllowList(nsIChannel* aChannel);
 
-  void SetFirstPartyDomain(nsIURI* aURI);
-  const nsAString& GetFirstPartyDomain() { return mFirstPartyDomain; };
+  void SetPartitionKey(nsIURI* aURI);
+  const nsAString& GetPartitionKey() { return mPartitionKey; };
 
   // Utility function to test if the passed cookiebahvior is
   // BEHAVIOR_REJECT_TRACKER, BEHAVIOR_REJECT_TRACKER_AND_PARTITION_FOREIGN or
@@ -170,7 +170,7 @@ class CookieJarSettings final : public nsICookieJarSettings {
   bool mIsFirstPartyIsolated;
   CookiePermissionList mCookiePermissions;
   bool mIsOnContentBlockingAllowList;
-  nsString mFirstPartyDomain;
+  nsString mPartitionKey;
 
   State mState;
 
diff --git a/netwerk/cookie/CookieService.cpp b/netwerk/cookie/CookieService.cpp
index 2cf15ae7f303..80371d00bcc8 100644
--- a/netwerk/cookie/CookieService.cpp
+++ b/netwerk/cookie/CookieService.cpp
@@ -1531,7 +1531,7 @@ CookieStatus CookieService::CheckPrefs(nsICookieJarSettings* aCookieJarSettings,
             ? nsIWebProgressListener::STATE_COOKIES_BLOCKED_FOREIGN
             : nsIWebProgressListener::STATE_COOKIES_BLOCKED_TRACKER;
     if (StoragePartitioningEnabled(rejectReason, aCookieJarSettings)) {
-      MOZ_ASSERT(!aOriginAttrs.mFirstPartyDomain.IsEmpty(),
+      MOZ_ASSERT(!aOriginAttrs.mPartitionKey.IsEmpty(),
                  "We must have a StoragePrincipal here!");
       return STATUS_ACCEPTED;
     }
diff --git a/netwerk/cookie/nsICookieJarSettings.idl b/netwerk/cookie/nsICookieJarSettings.idl
index 58c44efb49c5..6f8bf35cccf7 100644
--- a/netwerk/cookie/nsICookieJarSettings.idl
+++ b/netwerk/cookie/nsICookieJarSettings.idl
@@ -45,9 +45,9 @@ interface nsICookieJarSettings : nsISupports
   [infallible] readonly attribute boolean isOnContentBlockingAllowList;
 
   /**
-   * The domain for the top-level document.
+   * The key used for partitioning.
    */
-  readonly attribute AString firstPartyDomain;
+  readonly attribute AString partitionKey;
 
   /**
    * CookiePermission at the loading of the document for a particular
diff --git a/netwerk/ipc/NeckoChannelParams.ipdlh b/netwerk/ipc/NeckoChannelParams.ipdlh
index 1a11085475d1..461ee3bf311b 100644
--- a/netwerk/ipc/NeckoChannelParams.ipdlh
+++ b/netwerk/ipc/NeckoChannelParams.ipdlh
@@ -47,7 +47,7 @@ struct CookieJarSettingsArgs
   bool isOnContentBlockingAllowList;
   CookiePermissionData[] cookiePermissions;
   bool isFixed;
-  nsString firstPartyDomain;
+  nsString partitionKey;
 };
 
 //-----------------------------------------------------------------------------
diff --git a/netwerk/protocol/http/nsHttpChannel.cpp b/netwerk/protocol/http/nsHttpChannel.cpp
index 30ba0b0fad9b..d10d54944ee9 100644
--- a/netwerk/protocol/http/nsHttpChannel.cpp
+++ b/netwerk/protocol/http/nsHttpChannel.cpp
@@ -1869,7 +1869,7 @@ void nsHttpChannel::UpdateAntiTrackingInfo() {
     // We only need to set FPD for top-level loads. FPD will automatically be
     // propagated to non-top level loads via CookieJarSetting.
     mozilla::net::CookieJarSettings::Cast(cookieJarSettings)
-        ->SetFirstPartyDomain(mURI);
+        ->SetPartitionKey(mURI);
   }
 }
 
diff --git a/toolkit/components/antitracking/StoragePrincipalHelper.cpp b/toolkit/components/antitracking/StoragePrincipalHelper.cpp
index e079ac4c9bb6..d740ede9d79f 100644
--- a/toolkit/components/antitracking/StoragePrincipalHelper.cpp
+++ b/toolkit/components/antitracking/StoragePrincipalHelper.cpp
@@ -48,7 +48,7 @@ bool ChooseOriginAttributes(nsIChannel* aChannel, OriginAttributes& aAttrs,
   }
 
   nsAutoString partitionKey;
-  Unused << cjs->GetFirstPartyDomain(partitionKey);
+  Unused << cjs->GetPartitionKey(partitionKey);
 
   if (!partitionKey.IsEmpty()) {
     aAttrs.SetPartitionKey(partitionKey);