diff --git a/src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php b/src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php
index 19a83f30f7..3286f1f564 100644
--- a/src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php
+++ b/src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php
@@ -341,13 +341,13 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 
 		$comment = get_comment( $id );
 		if ( empty( $comment ) ) {
-			return new WP_Error( 'rest_comment_invalid_id', __( 'Invalid comment id.' ), array( 'status' => 404 ) );
+			return new WP_Error( 'rest_comment_invalid_id', __( 'Invalid comment ID.' ), array( 'status' => 404 ) );
 		}
 
 		if ( ! empty( $comment->comment_post_ID ) ) {
 			$post = get_post( $comment->comment_post_ID );
 			if ( empty( $post ) ) {
-				return new WP_Error( 'rest_post_invalid_id', __( 'Invalid post id.' ), array( 'status' => 404 ) );
+				return new WP_Error( 'rest_post_invalid_id', __( 'Invalid post ID.' ), array( 'status' => 404 ) );
 			}
 		}
 
@@ -611,7 +611,7 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 		$comment = get_comment( $id );
 
 		if ( empty( $comment ) ) {
-			return new WP_Error( 'rest_comment_invalid_id', __( 'Invalid comment id.' ), array( 'status' => 404 ) );
+			return new WP_Error( 'rest_comment_invalid_id', __( 'Invalid comment ID.' ), array( 'status' => 404 ) );
 		}
 
 		if ( isset( $request['type'] ) && get_comment_type( $id ) !== $request['type'] ) {
@@ -701,7 +701,7 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 		$comment = get_comment( $id );
 
 		if ( ! $comment ) {
-			return new WP_Error( 'rest_comment_invalid_id', __( 'Invalid comment id.' ), array( 'status' => 404 ) );
+			return new WP_Error( 'rest_comment_invalid_id', __( 'Invalid comment ID.' ), array( 'status' => 404 ) );
 		}
 
 		if ( ! $this->check_edit_permission( $comment ) ) {
@@ -726,7 +726,7 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 		$comment = get_comment( $id );
 
 		if ( empty( $comment ) ) {
-			return new WP_Error( 'rest_comment_invalid_id', __( 'Invalid comment id.' ), array( 'status' => 404 ) );
+			return new WP_Error( 'rest_comment_invalid_id', __( 'Invalid comment ID.' ), array( 'status' => 404 ) );
 		}
 
 		/**
diff --git a/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php b/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
index 434bff802c..183c1b03f9 100644
--- a/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
+++ b/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
@@ -423,7 +423,7 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 		$post = get_post( $id );
 
 		if ( empty( $id ) || empty( $post->ID ) || $this->post_type !== $post->post_type ) {
-			return new WP_Error( 'rest_post_invalid_id', __( 'Invalid post id.' ), array( 'status' => 404 ) );
+			return new WP_Error( 'rest_post_invalid_id', __( 'Invalid post ID.' ), array( 'status' => 404 ) );
 		}
 
 		$data     = $this->prepare_item_for_response( $post, $request );
@@ -619,7 +619,7 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 		$post = get_post( $id );
 
 		if ( empty( $id ) || empty( $post->ID ) || $this->post_type !== $post->post_type ) {
-			return new WP_Error( 'rest_post_invalid_id', __( 'Post id is invalid.' ), array( 'status' => 404 ) );
+			return new WP_Error( 'rest_post_invalid_id', __( 'Invalid post ID.' ), array( 'status' => 404 ) );
 		}
 
 		$post = $this->prepare_item_for_database( $request );
@@ -730,7 +730,7 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 		$post = get_post( $id );
 
 		if ( empty( $id ) || empty( $post->ID ) || $this->post_type !== $post->post_type ) {
-			return new WP_Error( 'rest_post_invalid_id', __( 'Invalid post id.' ), array( 'status' => 404 ) );
+			return new WP_Error( 'rest_post_invalid_id', __( 'Invalid post ID.' ), array( 'status' => 404 ) );
 		}
 
 		$supports_trash = ( EMPTY_TRASH_DAYS > 0 );