Index: wp-admin/js/revisions.js
===================================================================
--- wp-admin/js/revisions.js	(revision 24649)
+++ wp-admin/js/revisions.js	(working copy)
@@ -207,7 +207,7 @@
 					post_id: revisions.settings.postId
 				});
 
-				var deferred = wp.xhr.send( options );
+				var deferred = wp.ajax.send( options );
 				var requests = this.requests;
 
 				// Record that we're requesting each diff.
Index: wp-includes/js/media-models.js
===================================================================
--- wp-includes/js/media-models.js	(revision 24649)
+++ wp-includes/js/media-models.js	(working copy)
@@ -101,17 +101,17 @@
 		 * media.post( [action], [data] )
 		 *
 		 * Sends a POST request to WordPress.
-		 * See wp.xhr.post() in `wp-includes/js/wp-util.js`.
+		 * See wp.ajax.post() in `wp-includes/js/wp-util.js`.
 		 */
-		post: wp.xhr.post,
+		post: wp.ajax.post,
 
 		/**
 		 * media.ajax( [action], [options] )
 		 *
 		 * Sends an XHR request to WordPress.
-		 * See wp.xhr.send() in `wp-includes/js/wp-util.js`.
+		 * See wp.ajax.send() in `wp-includes/js/wp-util.js`.
 		 */
-		ajax: wp.xhr.send,
+		ajax: wp.ajax.send,
 
 		// Scales a set of dimensions to fit within bounding dimensions.
 		fit: function( dimensions ) {
Index: wp-includes/js/wp-util.js
===================================================================
--- wp-includes/js/wp-util.js	(revision 24649)
+++ wp-includes/js/wp-util.js	(working copy)
@@ -28,16 +28,16 @@
 		};
 	});
 
-	// wp.xhr
+	// wp.ajax
 	// ------
 	//
 	// Tools for sending ajax requests with JSON responses and built in error handling.
 	// Mirrors and wraps jQuery's ajax APIs.
-	wp.xhr = {
-		settings: settings.xhr || {},
+	wp.ajax = {
+		settings: settings.ajax || {},
 
 		/**
-		 * wp.xhr.post( [action], [data] )
+		 * wp.ajax.post( [action], [data] )
 		 *
 		 * Sends a POST request to WordPress.
 		 *
@@ -46,13 +46,13 @@
 		 * @return {$.promise}     A jQuery promise that represents the request.
 		 */
 		post: function( action, data ) {
-			return wp.xhr.send({
+			return wp.ajax.send({
 				data: _.isObject( action ) ? action : _.extend( data || {}, { action: action })
 			});
 		},
 
 		/**
-		 * wp.xhr.send( [action], [options] )
+		 * wp.ajax.send( [action], [options] )
 		 *
 		 * Sends a POST request to WordPress.
 		 *
@@ -70,7 +70,7 @@
 
 			options = _.defaults( options || {}, {
 				type:    'POST',
-				url:     wp.xhr.settings.url,
+				url:     wp.ajax.settings.url,
 				context: this
 			});
 
Index: wp-includes/script-loader.php
===================================================================
--- wp-includes/script-loader.php	(revision 24649)
+++ wp-includes/script-loader.php	(working copy)
@@ -269,7 +269,7 @@
 
 	$scripts->add( 'wp-util', "/wp-includes/js/wp-util$suffix.js", array('underscore', 'jquery'), false, 1 );
 	did_action( 'init' ) && $scripts->localize( 'wp-util', '_wpUtilSettings', array(
-		'xhr' => array(
+		'ajax' => array(
 			'url' => admin_url( 'admin-ajax.php', 'relative' ),
 		),
 	) );