diff --git a/.changeset/angry-candies-draw.md b/.changeset/angry-candies-draw.md
new file mode 100644
index 0000000000..fdf4d31994
--- /dev/null
+++ b/.changeset/angry-candies-draw.md
@@ -0,0 +1,5 @@
+---
+'@backstage/frontend-plugin-api': patch
+---
+
+The `source` property of `AppNodeSpec` has been renamed to `plugin`. The old property has been deprecated and will be removed in a future release.
diff --git a/.changeset/evil-lies-punch.md b/.changeset/evil-lies-punch.md
new file mode 100644
index 0000000000..e878c65731
--- /dev/null
+++ b/.changeset/evil-lies-punch.md
@@ -0,0 +1,6 @@
+---
+'@backstage/frontend-app-api': patch
+'@backstage/core-compat-api': patch
+---
+
+Updates to use the new `plugin` property of `AppNodeSpec`.
diff --git a/packages/core-compat-api/src/compatWrapper/BackwardsCompatProvider.tsx b/packages/core-compat-api/src/compatWrapper/BackwardsCompatProvider.tsx
index 151fb21067..0a5dd68aa3 100644
--- a/packages/core-compat-api/src/compatWrapper/BackwardsCompatProvider.tsx
+++ b/packages/core-compat-api/src/compatWrapper/BackwardsCompatProvider.tsx
@@ -119,7 +119,7 @@ function LegacyAppContextProvider(props: { children: ReactNode }) {
 
         const pluginSet = new Set<LegacyBackstagePlugin>();
         for (const node of tree.nodes.values()) {
-          const plugin = node.spec.source;
+          const plugin = node.spec.plugin;
           if (plugin) {
             pluginSet.add(toLegacyPlugin(plugin));
           }
diff --git a/packages/frontend-app-api/src/routing/RouteTracker.test.tsx b/packages/frontend-app-api/src/routing/RouteTracker.test.tsx
index 08a9673afc..5cee727075 100644
--- a/packages/frontend-app-api/src/routing/RouteTracker.test.tsx
+++ b/packages/frontend-app-api/src/routing/RouteTracker.test.tsx
@@ -49,7 +49,7 @@ describe('RouteTracker', () => {
       appNode: {
         spec: {
           extension: { id: 'home.page.index' },
-          source: { id: 'home' },
+          plugin: { id: 'home' },
         },
       } as AppNode,
     },
@@ -63,7 +63,7 @@ describe('RouteTracker', () => {
       appNode: {
         spec: {
           extension: { id: 'plugin1.page.index' },
-          source: { id: 'plugin1' },
+          plugin: { id: 'plugin1' },
         },
       } as AppNode,
     },
@@ -77,7 +77,7 @@ describe('RouteTracker', () => {
       appNode: {
         spec: {
           extension: { id: 'plugin2.page.index' },
-          source: { id: 'plugin2' },
+          plugin: { id: 'plugin2' },
         },
       } as AppNode,
     },
diff --git a/packages/frontend-app-api/src/routing/RouteTracker.tsx b/packages/frontend-app-api/src/routing/RouteTracker.tsx
index 4a218a0900..0068f87d4d 100644
--- a/packages/frontend-app-api/src/routing/RouteTracker.tsx
+++ b/packages/frontend-app-api/src/routing/RouteTracker.tsx
@@ -63,7 +63,7 @@ const getExtensionContext = (
       return acc;
     }, {});
 
-    const plugin = routeObject.appNode?.spec.source;
+    const plugin = routeObject.appNode?.spec.plugin;
     const extension = routeObject.appNode?.spec.extension;
 
     return {
diff --git a/packages/frontend-app-api/src/routing/extractRouteInfoFromAppNode.ts b/packages/frontend-app-api/src/routing/extractRouteInfoFromAppNode.ts
index 17afbeb4c9..a1abaf1599 100644
--- a/packages/frontend-app-api/src/routing/extractRouteInfoFromAppNode.ts
+++ b/packages/frontend-app-api/src/routing/extractRouteInfoFromAppNode.ts
@@ -124,8 +124,8 @@ export function extractRouteInfoFromAppNode(node: AppNode): {
 
       routeParents.set(routeRef, newParentRef);
       currentObj?.routeRefs.add(routeRef);
-      if (current.spec.source) {
-        currentObj?.plugins.add(toLegacyPlugin(current.spec.source));
+      if (current.spec.plugin) {
+        currentObj?.plugins.add(toLegacyPlugin(current.spec.plugin));
       }
     }
 
diff --git a/packages/frontend-app-api/src/tree/instantiateAppNodeTree.test.ts b/packages/frontend-app-api/src/tree/instantiateAppNodeTree.test.ts
index a000e016be..8801e2070e 100644
--- a/packages/frontend-app-api/src/tree/instantiateAppNodeTree.test.ts
+++ b/packages/frontend-app-api/src/tree/instantiateAppNodeTree.test.ts
@@ -57,6 +57,7 @@ function makeSpec<TConfig, TConfigInput>(
     disabled: extension.disabled,
     extension: extension as Extension<unknown, unknown>,
     source: undefined,
+    plugin: undefined,
     ...spec,
   };
 }
diff --git a/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.test.ts b/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.test.ts
index c486370563..979c851a47 100644
--- a/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.test.ts
+++ b/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.test.ts
@@ -126,6 +126,7 @@ describe('resolveAppNodeSpecs', () => {
         extension: makeExt('test/a'),
         attachTo: { id: 'root', input: 'default' },
         source: pluginA,
+        plugin: pluginA,
         disabled: false,
       },
     ]);
@@ -162,6 +163,7 @@ describe('resolveAppNodeSpecs', () => {
         id: 'test/a',
         extension: a,
         attachTo: { id: 'root', input: 'default' },
+        plugin,
         source: plugin,
         config: { foo: { bar: 1 } },
         disabled: false,
@@ -170,6 +172,7 @@ describe('resolveAppNodeSpecs', () => {
         id: 'test/b',
         extension: b,
         attachTo: { id: 'root', input: 'default' },
+        plugin,
         source: plugin,
         config: { foo: { qux: 3 } },
         disabled: false,
@@ -305,6 +308,7 @@ describe('resolveAppNodeSpecs', () => {
         id: 'test/a',
         extension: expect.objectContaining(aOverride),
         attachTo: { id: 'other', input: 'default' },
+        plugin,
         source: plugin,
         disabled: false,
       },
@@ -312,6 +316,7 @@ describe('resolveAppNodeSpecs', () => {
         id: 'test/b',
         extension: expect.objectContaining(bOverride),
         attachTo: { id: 'other', input: 'default' },
+        plugin,
         source: plugin,
         disabled: true,
       },
@@ -319,6 +324,7 @@ describe('resolveAppNodeSpecs', () => {
         id: 'test/c',
         extension: expect.objectContaining(cOverride),
         attachTo: { id: 'root', input: 'default' },
+        plugin,
         source: plugin,
         disabled: false,
       },
diff --git a/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.ts b/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.ts
index 3da68dcb50..399e6ccb7b 100644
--- a/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.ts
+++ b/packages/frontend-app-api/src/tree/resolveAppNodeSpecs.ts
@@ -46,23 +46,23 @@ export function resolveAppNodeSpecs(options: {
   const plugins = features.filter(OpaqueFrontendPlugin.isType);
   const modules = features.filter(isInternalFrontendModule);
 
-  const pluginExtensions = plugins.flatMap(source => {
-    return OpaqueFrontendPlugin.toInternal(source).extensions.map(
+  const pluginExtensions = plugins.flatMap(plugin => {
+    return OpaqueFrontendPlugin.toInternal(plugin).extensions.map(
       extension => ({
         ...extension,
-        source,
+        plugin,
       }),
     );
   });
   const moduleExtensions = modules.flatMap(mod =>
     toInternalFrontendModule(mod).extensions.flatMap(extension => {
       // Modules for plugins that are not installed are ignored
-      const source = plugins.find(p => p.id === mod.pluginId);
-      if (!source) {
+      const plugin = plugins.find(p => p.id === mod.pluginId);
+      if (!plugin) {
         return [];
       }
 
-      return [{ ...extension, source }];
+      return [{ ...extension, plugin }];
     }),
   );
 
@@ -70,7 +70,7 @@ export function resolveAppNodeSpecs(options: {
   if (pluginExtensions.some(({ id }) => forbidden.has(id))) {
     const pluginsStr = pluginExtensions
       .filter(({ id }) => forbidden.has(id))
-      .map(({ source }) => `'${source.id}'`)
+      .map(({ plugin }) => `'${plugin.id}'`)
       .join(', ');
     const forbiddenStr = [...forbidden].map(id => `'${id}'`).join(', ');
     throw new Error(
@@ -80,7 +80,7 @@ export function resolveAppNodeSpecs(options: {
   if (moduleExtensions.some(({ id }) => forbidden.has(id))) {
     const pluginsStr = moduleExtensions
       .filter(({ id }) => forbidden.has(id))
-      .map(({ source }) => `'${source.id}'`)
+      .map(({ plugin }) => `'${plugin.id}'`)
       .join(', ');
     const forbiddenStr = [...forbidden].map(id => `'${id}'`).join(', ');
     throw new Error(
@@ -89,12 +89,13 @@ export function resolveAppNodeSpecs(options: {
   }
 
   const configuredExtensions = [
-    ...pluginExtensions.map(({ source, ...extension }) => {
+    ...pluginExtensions.map(({ plugin, ...extension }) => {
       const internalExtension = toInternalExtension(extension);
       return {
         extension: internalExtension,
         params: {
-          source,
+          plugin,
+          source: plugin,
           attachTo: internalExtension.attachTo,
           disabled: internalExtension.disabled,
           config: undefined as unknown,
@@ -107,6 +108,7 @@ export function resolveAppNodeSpecs(options: {
         extension: internalExtension,
         params: {
           source: undefined,
+          plugin: undefined,
           attachTo: internalExtension.attachTo,
           disabled: internalExtension.disabled,
           config: undefined as unknown,
@@ -133,7 +135,8 @@ export function resolveAppNodeSpecs(options: {
       configuredExtensions.push({
         extension: internalExtension,
         params: {
-          source: extension.source,
+          plugin: extension.plugin,
+          source: extension.plugin,
           attachTo: internalExtension.attachTo,
           disabled: internalExtension.disabled,
           config: undefined,
@@ -219,6 +222,7 @@ export function resolveAppNodeSpecs(options: {
     attachTo: param.params.attachTo,
     extension: param.extension,
     disabled: param.params.disabled,
+    plugin: param.params.plugin,
     source: param.params.source,
     config: param.params.config,
   }));
diff --git a/packages/frontend-plugin-api/report.api.md b/packages/frontend-plugin-api/report.api.md
index cd5d89401d..1c01e0ac83 100644
--- a/packages/frontend-plugin-api/report.api.md
+++ b/packages/frontend-plugin-api/report.api.md
@@ -235,6 +235,8 @@ export interface AppNodeSpec {
   // (undocumented)
   readonly id: string;
   // (undocumented)
+  readonly plugin?: FrontendPlugin;
+  // @deprecated (undocumented)
   readonly source?: FrontendPlugin;
 }
 
diff --git a/packages/frontend-plugin-api/src/apis/definitions/AppTreeApi.ts b/packages/frontend-plugin-api/src/apis/definitions/AppTreeApi.ts
index c9d9896600..0c6dde3cc8 100644
--- a/packages/frontend-plugin-api/src/apis/definitions/AppTreeApi.ts
+++ b/packages/frontend-plugin-api/src/apis/definitions/AppTreeApi.ts
@@ -37,6 +37,10 @@ export interface AppNodeSpec {
   readonly extension: Extension<unknown, unknown>;
   readonly disabled: boolean;
   readonly config?: unknown;
+  readonly plugin?: FrontendPlugin;
+  /**
+   * @deprecated Use {@link AppNodeSpec.plugin} instead.
+   */
   readonly source?: FrontendPlugin;
 }
 
diff --git a/packages/frontend-plugin-api/src/components/ExtensionBoundary.tsx b/packages/frontend-plugin-api/src/components/ExtensionBoundary.tsx
index 46b3956e0e..a55afeeffd 100644
--- a/packages/frontend-plugin-api/src/components/ExtensionBoundary.tsx
+++ b/packages/frontend-plugin-api/src/components/ExtensionBoundary.tsx
@@ -69,14 +69,14 @@ export function ExtensionBoundary(props: ExtensionBoundaryProps) {
     node.instance?.getData(coreExtensionData.routePath),
   );
 
-  const plugin = node.spec.source;
+  const plugin = node.spec.plugin;
   const Progress = useComponentRef(coreComponentRefs.progress);
   const fallback = useComponentRef(coreComponentRefs.errorBoundaryFallback);
 
   // Skipping "routeRef" attribute in the new system, the extension "id" should provide more insight
   const attributes = {
     extensionId: node.spec.id,
-    pluginId: node.spec.source?.id ?? 'app',
+    pluginId: node.spec.plugin?.id ?? 'app',
   };
 
   return (