diff --git a/core/lib/Drupal/Core/Render/BareHtmlPageRenderer.php b/core/lib/Drupal/Core/Render/BareHtmlPageRenderer.php
index a7164d9..f95d992 100644
--- a/core/lib/Drupal/Core/Render/BareHtmlPageRenderer.php
+++ b/core/lib/Drupal/Core/Render/BareHtmlPageRenderer.php
@@ -52,7 +52,7 @@ public function renderBarePage(array $content, $title, $page_theme_property, arr
       '#type' => 'html',
       '#attributes' => $attributes,
       'page' => [
-        '#type' => 'page',
+        '#type' => 'body',
         '#theme' => $page_theme_property,
         '#title' => $title,
         'content' => $content,
diff --git a/core/lib/Drupal/Core/Render/Element/Page.php b/core/lib/Drupal/Core/Render/Element/Body.php
similarity index 77%
rename from core/lib/Drupal/Core/Render/Element/Page.php
rename to core/lib/Drupal/Core/Render/Element/Body.php
index b73c808d..46c839a 100644
--- a/core/lib/Drupal/Core/Render/Element/Page.php
+++ b/core/lib/Drupal/Core/Render/Element/Body.php
@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Contains \Drupal\Core\Render\Element\Page.
+ * Contains \Drupal\Core\Render\Element\Body.
  */
 
 namespace Drupal\Core\Render\Element;
@@ -12,9 +12,9 @@
  *
  * This represents the "main part" of the HTML page's body; see html.html.twig.
  *
- * @RenderElement("page")
+ * @RenderElement("body")
  */
-class Page extends RenderElement {
+class Body extends RenderElement {
 
   /**
    * {@inheritdoc}
diff --git a/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php b/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php
index 7e06aab..fa7a56e 100644
--- a/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php
+++ b/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php
@@ -208,7 +208,7 @@ protected function prepare(array $main_content, Request $request, RouteMatchInte
       // Generate a #type => page render array using the page display variant,
       // the page display will build the content for the various page regions.
       $page = array(
-        '#type' => 'page',
+        '#type' => 'body',
       );
       $page += $page_display->build();
     }
diff --git a/core/modules/block/src/Controller/BlockController.php b/core/modules/block/src/Controller/BlockController.php
index 66ecbbd..1bb926a 100644
--- a/core/modules/block/src/Controller/BlockController.php
+++ b/core/modules/block/src/Controller/BlockController.php
@@ -56,7 +56,7 @@ public static function create(ContainerInterface $container) {
   public function demo($theme) {
     $page = [
       '#title' => $this->themeHandler->getName($theme),
-      '#type' => 'page',
+      '#type' => 'body',
       '#attached' => array(
         'drupalSettings' => [
           // The block demonstration page is not marked as an administrative
diff --git a/core/modules/system/src/Controller/BatchController.php b/core/modules/system/src/Controller/BatchController.php
index 9a0e8f0..64f6645 100644
--- a/core/modules/system/src/Controller/BatchController.php
+++ b/core/modules/system/src/Controller/BatchController.php
@@ -67,7 +67,7 @@ public function batchPage(Request $request) {
     }
     elseif (isset($output)) {
       $page = [
-        '#type' => 'page',
+        '#type' => 'body',
         '#show_messages' => FALSE,
         'content' => $output,
       ];
diff --git a/core/modules/system/tests/modules/error_test/src/Controller/ErrorTestController.php b/core/modules/system/tests/modules/error_test/src/Controller/ErrorTestController.php
index 25ef1c5..ea0f796 100644
--- a/core/modules/system/tests/modules/error_test/src/Controller/ErrorTestController.php
+++ b/core/modules/system/tests/modules/error_test/src/Controller/ErrorTestController.php
@@ -88,7 +88,7 @@ public function triggerPDOException() {
    */
   public function triggerRendererException() {
     return [
-      '#type' => 'page',
+      '#type' => 'body',
       '#post_render' => [
         function () {
           throw new \Exception('This is an exception that occurs during rendering');
diff --git a/core/tests/Drupal/Tests/Core/Render/ElementInfoManagerTest.php b/core/tests/Drupal/Tests/Core/Render/ElementInfoManagerTest.php
index b0ca1f7..75894ec 100644
--- a/core/tests/Drupal/Tests/Core/Render/ElementInfoManagerTest.php
+++ b/core/tests/Drupal/Tests/Core/Render/ElementInfoManagerTest.php
@@ -124,7 +124,7 @@ public function providerTestGetInfo() {
     $data[] = array(
       'page',
       array(
-        '#type' => 'page',
+        '#type' => 'body',
         '#theme' => 'page',
         '#defaults_loaded' => TRUE,
       ),
@@ -146,7 +146,7 @@ public function providerTestGetInfo() {
     $data[] = array(
       'page',
       array(
-        '#type' => 'page',
+        '#type' => 'body',
         '#theme' => 'page',
         '#number' => 597219,
         '#defaults_loaded' => TRUE,
@@ -218,7 +218,7 @@ public function providerTestGetInfoElementPlugin() {
     $data[] = array(
       'Drupal\Core\Render\Element\ElementInterface',
       array(
-        '#type' => 'page',
+        '#type' => 'body',
         '#theme' => 'page',
         '#defaults_loaded' => TRUE,
       ),
@@ -227,7 +227,7 @@ public function providerTestGetInfoElementPlugin() {
     $data[] = array(
       'Drupal\Core\Render\Element\FormElementInterface',
       array(
-        '#type' => 'page',
+        '#type' => 'body',
         '#theme' => 'page',
         '#input' => TRUE,
         '#value_callback' => array('TestElementPlugin', 'valueCallback'),