diff -u b/core/core.api.php b/core/core.api.php
--- b/core/core.api.php
+++ b/core/core.api.php
@@ -2373,16 +2373,16 @@
  *   Ajax event. More information on callbacks is below in @ref sub_callback.
  * - wrapper: The HTML 'id' attribute of the area where the content returned by
  *   the callback should be placed. Note that callbacks have a choice of
- *   returning content or JavaScript commands; 'wrapper_selector' is used for content
+ *   returning content or JavaScript commands; 'selector' is used for content
  *   returns.
  * - method: The jQuery method for placing the new content (used with
- *   'wrapper_selector'). Valid options are 'replaceWith' (default), 'append', 'prepend',
+ *   'selector'). Valid options are 'replaceWith' (default), 'append', 'prepend',
  *   'before', 'after', or 'html'. See
  *   http://api.jquery.com/category/manipulation/ for more information on these
  *   methods.
  * - effect: The jQuery effect to use when placing the new HTML (used with
- *   'wrapper_selector'). Valid options are 'none' (default), 'slide', or 'fade'.
- * - speed: The effect speed to use (used with 'effect' and 'wrapper_selector'). Valid
+ *   'selector'). Valid options are 'none' (default), 'slide', or 'fade'.
+ * - speed: The effect speed to use (used with 'effect' and 'selector'). Valid
  *   options are 'slow' (default), 'fast', or the number of milliseconds the
  *   effect should run.
  * - event: The JavaScript event to respond to. This is selected automatically
@@ -2424,7 +2424,7 @@
  * Once you have processed the input, you have your choice of returning HTML
  * markup or a set of Ajax commands. If you choose to return HTML markup, you
  * can return it as a string or a renderable array, and it will be placed in
- * the defined 'wrapper_selector' element (see documentation above in
+ * the defined 'selector' element (see documentation above in
  * @ref sub_form). In addition, any messages returned by
  * \Drupal\Core\Messenger\Messenger::all(), themed as in
  * status-messages.html.twig, will be prepended.
@@ -2449,7 +2449,7 @@
  * invokes an arbitrary jQuery command.
  *
  * As noted above, status messages are prepended automatically if you use the
- * 'wrapper_selector' method and return HTML markup. This is not the case if you return
+ * 'selector' method and return HTML markup. This is not the case if you return
  * commands, but if you would like to show status messages, you can add
  * @code
  * array('#type' => 'status_messages')
diff -u b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
--- b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
@@ -637,7 +637,7 @@
     if (!empty($element['#ajax'])) {
       $element['#ajax'] = [
         'callback' => [get_called_class(), 'settingsAjax'],
-        'wrapper_selector' => '#' . $main_form['#id'],
+        'selector' => '#' . $main_form['#id'],
         'element' => $main_form['#array_parents'],
       ];
     }
diff -u b/core/lib/Drupal/Core/Field/WidgetBase.php b/core/lib/Drupal/Core/Field/WidgetBase.php
--- b/core/lib/Drupal/Core/Field/WidgetBase.php
+++ b/core/lib/Drupal/Core/Field/WidgetBase.php
@@ -249,7 +249,7 @@
           '#submit' => [[get_class($this), 'addMoreSubmit']],
           '#ajax' => [
             'callback' => [get_class($this), 'addMoreAjax'],
-            'wrapper_selector' => '#' . $wrapper_id,
+            'selector' => '#' . $wrapper_id,
             'effect' => 'fade',
           ],
         ];
diff -u b/core/lib/Drupal/Core/Render/Element/RenderElement.php b/core/lib/Drupal/Core/Render/Element/RenderElement.php
--- b/core/lib/Drupal/Core/Render/Element/RenderElement.php
+++ b/core/lib/Drupal/Core/Render/Element/RenderElement.php
@@ -243,7 +243,7 @@
    *   - #ajax['url']
    *   - #ajax['callback']
    *   - #ajax['options']
-   *   - #ajax['wrapper_selector']
+   *   - #ajax['selector']
    *   - #ajax['parameters']
    *   - #ajax['effect']
    *   - #ajax['accepts']
@@ -328,10 +328,10 @@
 
       $settings = $element['#ajax'];
 
-      // @todo Remove support for 'wrapper' and solely use 'wrapper_selector'.
+      // @todo Remove support for 'wrapper' and solely use 'selector'.
       if (isset($settings['wrapper'])) {
-        @trigger_error('Use of "wrapper" is deprecated in Drupal 8.7.x and will be removed before Drupal 9.0.0. Use "wrapper_selector" instead and prefix the value with either "#" for IDs or "." for classes.', E_USER_DEPRECATED);
-        $settings['wrapper_selector'] = '#' . $settings['wrapper'];
+        @trigger_error('Use of "wrapper" is deprecated in Drupal 8.7.x and will be removed before Drupal 9.0.0. Use "selector" instead and prefix the value with either "#" for IDs or "." for classes.', E_USER_DEPRECATED);
+        $settings['selector'] = '#' . $settings['wrapper'];
         unset($settings['wrapper']);
       }
 
diff -u b/core/misc/ajax.es6.js b/core/misc/ajax.es6.js
--- b/core/misc/ajax.es6.js
+++ b/core/misc/ajax.es6.js
@@ -7,7 +7,7 @@
  * then executed to make any changes that are necessary to the page.
  *
  * Drupal uses this file to enhance form elements with `#ajax['url']` and
- * `#ajax['wrapper_selector']` properties. If set, this file will automatically be
+ * `#ajax['selector']` properties. If set, this file will automatically be
  * included to provide Ajax capabilities.
  */
 
@@ -360,7 +360,7 @@
    * then executed to make any changes that are necessary to the page.
    *
    * Drupal uses this file to enhance form elements with `#ajax['url']` and
-   * `#ajax['wrapper_selector']` properties. If set, this file will automatically be
+   * `#ajax['selector']` properties. If set, this file will automatically be
    * included to provide Ajax capabilities.
    *
    * @constructor
@@ -402,19 +402,19 @@
      */
     this.instanceIndex = false;
 
-    // @todo Remove support for 'wrapper' and solely use 'wrapper_selector'.
-    if (this.wrapper && !this.wrapper_selector) {
+    // @todo Remove support for 'wrapper' and solely use 'selector'.
+    if (this.wrapper && !this.selector) {
       /**
        * @type {string}
        */
-      this.wrapper_selector = `#${this.wrapper}`;
+      this.selector = `#${this.wrapper}`;
 
       /**
-       * @deprecated Use this.wrapper_selector.
+       * @deprecated Use this.selector.
        *
        * @type {string}
        */
-      this.wrapper = this.wrapper_selector;
+      this.wrapper = this.selector;
     }
 
     /**
@@ -1089,7 +1089,7 @@
       this.progress.object.stopMonitoring();
     }
     // Undo hide.
-    $(this.wrapper_selector).show();
+    $(this.selector).show();
     // Re-enable the element.
     $(this.element).prop('disabled', false);
     // Reattach behaviors, if they were detached in beforeSerialize(), and the
@@ -1205,7 +1205,7 @@
       // our presets.
       const $wrapper = response.selector
         ? $(response.selector)
-        : $(ajax.wrapper_selector);
+        : $(ajax.selector);
       const method = response.method || ajax.method;
       const effect = ajax.getEffect(response);
 
@@ -1259,7 +1259,7 @@
 
       // Attach all JavaScript behaviors to the new content, if it was
       // successfully added to the page, this if statement allows
-      // `#ajax['wrapper_selector']` to be optional.
+      // `#ajax['selector']` to be optional.
       if ($newContent.parents('html').length) {
         // Attach behaviors to all element nodes.
         $newContent.each((index, element) => {
diff -u b/core/misc/ajax.js b/core/misc/ajax.js
--- b/core/misc/ajax.js
+++ b/core/misc/ajax.js
@@ -172,10 +172,10 @@
 
     this.instanceIndex = false;
 
-    if (this.wrapper && !this.wrapper_selector) {
-      this.wrapper_selector = '#' + this.wrapper;
+    if (this.wrapper && !this.selector) {
+      this.selector = '#' + this.wrapper;
 
-      this.wrapper = this.wrapper_selector;
+      this.wrapper = this.selector;
     }
 
     this.element = element;
@@ -491,7 +491,7 @@
       this.progress.object.stopMonitoring();
     }
 
-    $(this.wrapper_selector).show();
+    $(this.selector).show();
 
     $(this.element).prop('disabled', false);
 
@@ -515,7 +515,7 @@
   Drupal.AjaxCommands = function () {};
   Drupal.AjaxCommands.prototype = {
     insert: function insert(ajax, response) {
-      var $wrapper = response.selector ? $(response.selector) : $(ajax.wrapper_selector);
+      var $wrapper = response.selector ? $(response.selector) : $(ajax.selector);
       var method = response.method || ajax.method;
       var effect = ajax.getEffect(response);
 
diff -u b/core/modules/action/tests/action_form_ajax_test/src/Plugin/Action/ActionAjaxTest.php b/core/modules/action/tests/action_form_ajax_test/src/Plugin/Action/ActionAjaxTest.php
--- b/core/modules/action/tests/action_form_ajax_test/src/Plugin/Action/ActionAjaxTest.php
+++ b/core/modules/action/tests/action_form_ajax_test/src/Plugin/Action/ActionAjaxTest.php
@@ -50,7 +50,7 @@
       '#type' => 'checkbox',
       '#title' => $this->t('Are we having a party?'),
       '#ajax' => [
-        'wrapper_selector' => '#party-container',
+        'selector' => '#party-container',
         'callback' => [$this, 'partyCallback'],
       ],
       '#default_value' => $having_a_party,
diff -u b/core/modules/block/src/BlockForm.php b/core/modules/block/src/BlockForm.php
--- b/core/modules/block/src/BlockForm.php
+++ b/core/modules/block/src/BlockForm.php
@@ -170,7 +170,7 @@
         '#default_value' => $theme,
         '#ajax' => [
           'callback' => '::themeSwitch',
-          'wrapper_selector' => '#edit-block-region-wrapper',
+          'selector' => '#edit-block-region-wrapper',
         ],
       ];
     }
diff -u b/core/modules/book/src/BookManager.php b/core/modules/book/src/BookManager.php
--- b/core/modules/book/src/BookManager.php
+++ b/core/modules/book/src/BookManager.php
@@ -244,7 +244,7 @@
       '#attributes' => ['class' => ['book-title-select']],
       '#ajax' => [
         'callback' => 'book_form_update',
-        'wrapper_selector' => '#edit-book-plid-wrapper',
+        'selector' => '#edit-book-plid-wrapper',
         'effect' => 'fade',
         'speed' => 'fast',
       ],
diff -u b/core/modules/config/src/Form/ConfigSingleExportForm.php b/core/modules/config/src/Form/ConfigSingleExportForm.php
--- b/core/modules/config/src/Form/ConfigSingleExportForm.php
+++ b/core/modules/config/src/Form/ConfigSingleExportForm.php
@@ -95,7 +95,7 @@
       '#default_value' => $config_type,
       '#ajax' => [
         'callback' => '::updateConfigurationType',
-        'wrapper_selector' => '#edit-config-type-wrapper',
+        'selector' => '#edit-config-type-wrapper',
       ],
     ];
     $default_type = $form_state->getValue('config_type', $config_type);
@@ -108,7 +108,7 @@
       '#suffix' => '</div>',
       '#ajax' => [
         'callback' => '::updateExport',
-        'wrapper_selector' => '#edit-export-wrapper',
+        'selector' => '#edit-export-wrapper',
       ],
     ];
 
diff -u b/core/modules/config/tests/config_test/src/ConfigTestForm.php b/core/modules/config/tests/config_test/src/ConfigTestForm.php
--- b/core/modules/config/tests/config_test/src/ConfigTestForm.php
+++ b/core/modules/config/tests/config_test/src/ConfigTestForm.php
@@ -73,7 +73,7 @@
       '#default_value' => $size,
       '#ajax' => [
         'callback' => '::updateSize',
-        'wrapper_selector' => '#size-wrapper',
+        'selector' => '#size-wrapper',
       ],
     ];
     $form['size_wrapper']['size_submit'] = [
diff -u b/core/modules/editor/editor.module b/core/modules/editor/editor.module
--- b/core/modules/editor/editor.module
+++ b/core/modules/editor/editor.module
@@ -130,7 +130,7 @@
     '#ajax' => [
       'trigger_as' => ['name' => 'editor_configure'],
       'callback' => 'editor_form_filter_admin_form_ajax',
-      'wrapper_selector' => '#editor-settings-wrapper',
+      'selector' => '#editor-settings-wrapper',
     ],
     '#weight' => -10,
   ];
@@ -142,7 +142,7 @@
     '#submit' => ['editor_form_filter_admin_format_editor_configure'],
     '#ajax' => [
       'callback' => 'editor_form_filter_admin_form_ajax',
-      'wrapper_selector' => '#editor-settings-wrapper',
+      'selector' => '#editor-settings-wrapper',
     ],
     '#weight' => -10,
     '#attributes' => ['class' => ['js-hide']],
diff -u b/core/modules/field_layout/src/Form/FieldLayoutEntityDisplayFormTrait.php b/core/modules/field_layout/src/Form/FieldLayoutEntityDisplayFormTrait.php
--- b/core/modules/field_layout/src/Form/FieldLayoutEntityDisplayFormTrait.php
+++ b/core/modules/field_layout/src/Form/FieldLayoutEntityDisplayFormTrait.php
@@ -65,7 +65,7 @@
       '#default_value' => $layout_plugin->getPluginId(),
       '#ajax' => [
         'callback' => '::settingsAjax',
-        'wrapper_selector' => '#field-layout-settings-wrapper',
+        'selector' => '#field-layout-settings-wrapper',
         'trigger_as' => ['name' => 'field_layout_change'],
       ],
     ];
@@ -77,7 +77,7 @@
       '#attributes' => ['class' => ['js-hide']],
       '#ajax' => [
         'callback' => '::settingsAjax',
-        'wrapper_selector' => '#field-layout-settings-wrapper',
+        'selector' => '#field-layout-settings-wrapper',
       ],
     ];
 
diff -u b/core/modules/field_ui/src/Form/EntityDisplayFormBase.php b/core/modules/field_ui/src/Form/EntityDisplayFormBase.php
--- b/core/modules/field_ui/src/Form/EntityDisplayFormBase.php
+++ b/core/modules/field_ui/src/Form/EntityDisplayFormBase.php
@@ -236,7 +236,7 @@
       '#submit' => ['::multistepSubmit'],
       '#ajax' => [
         'callback' => '::multistepAjax',
-        'wrapper_selector' => '#field-display-overview-wrapper',
+        'selector' => '#field-display-overview-wrapper',
         'effect' => 'fade',
         // The button stays hidden, so we hide the Ajax spinner too. Ad-hoc
         // spinners will be added manually by the client-side script.
@@ -348,7 +348,7 @@
       '#submit' => ['::multistepSubmit'],
       '#ajax' => [
         'callback' => '::multistepAjax',
-        'wrapper_selector' => '#field-display-overview-wrapper',
+        'selector' => '#field-display-overview-wrapper',
         'effect' => 'fade',
       ],
       '#field_name' => $field_name,
diff -u b/core/modules/file/src/Element/ManagedFile.php b/core/modules/file/src/Element/ManagedFile.php
--- b/core/modules/file/src/Element/ManagedFile.php
+++ b/core/modules/file/src/Element/ManagedFile.php
@@ -230,7 +230,7 @@
           'element_parents' => implode('/', $element['#array_parents']),
         ],
       ],
-      'wrapper_selector' => '#' . $ajax_wrapper_id,
+      'selector' => '#' . $ajax_wrapper_id,
       'effect' => 'fade',
       'progress' => [
         'type' => $element['#progress_indicator'],
diff -u b/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php b/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php
--- b/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php
+++ b/core/modules/file/src/Plugin/Field/FieldWidget/FileWidget.php
@@ -430,7 +430,7 @@
       foreach (Element::children($element) as $key) {
         if (isset($element[$key]['#ajax'])) {
           $element[$key]['#ajax']['options'] = $new_options;
-          $element[$key]['#ajax']['wrapper_selector'] = $new_wrapper;
+          $element[$key]['#ajax']['selector'] = $new_wrapper;
         }
       }
       unset($element['#prefix'], $element['#suffix']);
diff -u b/core/modules/layout_builder/src/Plugin/Block/FieldBlock.php b/core/modules/layout_builder/src/Plugin/Block/FieldBlock.php
--- b/core/modules/layout_builder/src/Plugin/Block/FieldBlock.php
+++ b/core/modules/layout_builder/src/Plugin/Block/FieldBlock.php
@@ -251,7 +251,7 @@
       '#default_value' => $config['formatter']['type'],
       '#ajax' => [
         'callback' => [static::class, 'formatterSettingsAjaxCallback'],
-        'wrapper_selector' => '#formatter-settings-wrapper',
+        'selector' => '#formatter-settings-wrapper',
       ],
     ];
 
diff -u b/core/modules/layout_builder/tests/modules/layout_builder_test/src/Plugin/Block/TestAjaxBlock.php b/core/modules/layout_builder/tests/modules/layout_builder_test/src/Plugin/Block/TestAjaxBlock.php
--- b/core/modules/layout_builder/tests/modules/layout_builder_test/src/Plugin/Block/TestAjaxBlock.php
+++ b/core/modules/layout_builder/tests/modules/layout_builder_test/src/Plugin/Block/TestAjaxBlock.php
@@ -32,7 +32,7 @@
         '@time' => time(),
       ]),
       '#ajax' => [
-        'wrapper_selector' => '#test-ajax-wrapper',
+        'selector' => '#test-ajax-wrapper',
         'callback' => [$this, 'ajaxCallback'],
       ],
     ];
diff -u b/core/modules/media_library/src/Form/AddFormBase.php b/core/modules/media_library/src/Form/AddFormBase.php
--- b/core/modules/media_library/src/Form/AddFormBase.php
+++ b/core/modules/media_library/src/Form/AddFormBase.php
@@ -266,7 +266,7 @@
         '#value' => $this->t('Save'),
         '#ajax' => [
           'callback' => '::updateWidget',
-          'wrapper_selector' => '#media-library-add-form-wrapper',
+          'selector' => '#media-library-add-form-wrapper',
         ],
       ],
     ];
diff -u b/core/modules/media_library/src/Form/FileUploadForm.php b/core/modules/media_library/src/Form/FileUploadForm.php
--- b/core/modules/media_library/src/Form/FileUploadForm.php
+++ b/core/modules/media_library/src/Form/FileUploadForm.php
@@ -178,7 +178,7 @@
     $element['upload_button']['#submit'] = ['::uploadButtonSubmit'];
     $element['upload_button']['#ajax'] = [
       'callback' => '::updateFormCallback',
-      'wrapper_selector' => '#media-library-wrapper',
+      'selector' => '#media-library-wrapper',
     ];
     return $element;
   }
diff -u b/core/modules/media_library/src/Plugin/Field/FieldWidget/MediaLibraryWidget.php b/core/modules/media_library/src/Plugin/Field/FieldWidget/MediaLibraryWidget.php
--- b/core/modules/media_library/src/Plugin/Field/FieldWidget/MediaLibraryWidget.php
+++ b/core/modules/media_library/src/Plugin/Field/FieldWidget/MediaLibraryWidget.php
@@ -337,7 +337,7 @@
             ],
             '#ajax' => [
               'callback' => [static::class, 'updateWidget'],
-              'wrapper_selector' => '#' . $wrapper_id,
+              'selector' => '#' . $wrapper_id,
             ],
             '#submit' => [[static::class, 'removeItem']],
             // Prevent errors in other widgets from preventing removal.
@@ -425,7 +425,7 @@
       '#name' => $field_name . '-media-library-update' . $id_suffix,
       '#ajax' => [
         'callback' => [static::class, 'updateWidget'],
-        'wrapper_selector' => '#' . $wrapper_id,
+        'selector' => '#' . $wrapper_id,
       ],
       '#attributes' => [
         'data-media-library-widget-update' => $field_name . $id_suffix,
diff -u b/core/modules/responsive_image/src/ResponsiveImageStyleForm.php b/core/modules/responsive_image/src/ResponsiveImageStyleForm.php
--- b/core/modules/responsive_image/src/ResponsiveImageStyleForm.php
+++ b/core/modules/responsive_image/src/ResponsiveImageStyleForm.php
@@ -100,7 +100,7 @@
       '#description' => $description,
       '#ajax' => [
         'callback' => '::breakpointMappingFormAjax',
-        'wrapper_selector' => '#responsive-image-style-breakpoints-wrapper',
+        'selector' => '#responsive-image-style-breakpoints-wrapper',
       ],
     ];
 
diff -u b/core/modules/simpletest/src/WebTestBase.php b/core/modules/simpletest/src/WebTestBase.php
--- b/core/modules/simpletest/src/WebTestBase.php
+++ b/core/modules/simpletest/src/WebTestBase.php
@@ -1247,10 +1247,10 @@
 
         case 'insert':
           $wrapperNode = NULL;
-          // When a command doesn't specify a selector, use #ajax['wrapper_selector'].
+          // When a command doesn't specify a selector, use #ajax['selector'].
           if (!isset($command['selector'])) {
-            $selector_type = substr($ajax_settings['wrapper_selector'], 0, 1);
-            $selector = substr($ajax_settings['wrapper_selector'], 1);
+            $selector_type = substr($ajax_settings['selector'], 0, 1);
+            $selector = substr($ajax_settings['selector'], 1);
             if ($selector_type === '#') {
               $wrapperNode = $xpath->query('//*[@id="' . $selector . '"]')->item(0);
             }
diff -u b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestAjaxElementsForm.php b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestAjaxElementsForm.php
--- b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestAjaxElementsForm.php
+++ b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestAjaxElementsForm.php
@@ -39,7 +39,7 @@
       '#type' => 'datetime',
       '#ajax' => [
         'callback' => [$callback_object, 'datetimeCallback'],
-        'wrapper_selector' => '#ajax_datetime_value',
+        'selector' => '#ajax_datetime_value',
       ],
     ];
 
diff -u b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestLazyLoadForm.php b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestLazyLoadForm.php
--- b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestLazyLoadForm.php
+++ b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestLazyLoadForm.php
@@ -37,7 +37,7 @@
       '#type' => 'submit',
       '#value' => $this->t('Submit'),
       '#ajax' => [
-        'wrapper_selector' => '#ajax-forms-test-lazy-load-ajax-wrapper',
+        'selector' => '#ajax-forms-test-lazy-load-ajax-wrapper',
         'callback' => 'ajax_forms_test_lazy_load_form_ajax',
       ],
       '#prefix' => '<div id="ajax-forms-test-lazy-load-ajax-wrapper"></div>',
diff -u b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestSimpleForm.php b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestSimpleForm.php
--- b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestSimpleForm.php
+++ b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestSimpleForm.php
@@ -86,7 +86,7 @@
         '#title' => $this->t('AJAX checkbox in a group'),
         '#ajax' => [
           'callback' => [$object, 'checkboxGroupCallback'],
-          'wrapper_selector' => '#checkbox-wrapper',
+          'selector' => '#checkbox-wrapper',
         ],
       ],
       'nested_group' => [
@@ -100,7 +100,7 @@
         '#title' => $this->t('AJAX checkbox in a nested group'),
         '#ajax' => [
           'callback' => [$object, 'checkboxGroupCallback'],
-          'wrapper_selector' => '#checkbox-wrapper',
+          'selector' => '#checkbox-wrapper',
         ],
       ],
     ];
diff -u b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestValidationForm.php b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestValidationForm.php
--- b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestValidationForm.php
+++ b/core/modules/system/tests/modules/ajax_forms_test/src/Form/AjaxFormsTestValidationForm.php
@@ -30,7 +30,7 @@
       '#default_value' => $form_state->getValue('drivertext', ''),
       '#ajax' => [
         'callback' => 'ajax_forms_test_validation_form_callback',
-        'wrapper_selector' => '#message_area',
+        'selector' => '#message_area',
         'method' => 'replace',
       ],
       '#suffix' => '<div id="message_area"></div>',
@@ -43,7 +43,7 @@
       '#default_value' => $form_state->getValue('drivernumber', ''),
       '#ajax' => [
         'callback' => 'ajax_forms_test_validation_number_form_callback',
-        'wrapper_selector' => '#message_area_number',
+        'selector' => '#message_area_number',
         'method' => 'replace',
       ],
       '#suffix' => '<div id="message_area_number"></div>',
diff -u b/core/modules/system/tests/modules/ajax_forms_test/src/Plugin/Block/AjaxFormBlock.php b/core/modules/system/tests/modules/ajax_forms_test/src/Plugin/Block/AjaxFormBlock.php
--- b/core/modules/system/tests/modules/ajax_forms_test/src/Plugin/Block/AjaxFormBlock.php
+++ b/core/modules/system/tests/modules/ajax_forms_test/src/Plugin/Block/AjaxFormBlock.php
@@ -96,7 +96,7 @@
       ],
       '#ajax' => [
         'callback' => '::updateOptions',
-        'wrapper_selector' => '#edit-test1-wrapper',
+        'selector' => '#edit-test1-wrapper',
       ],
       '#prefix' => '<div id="edit-test1-wrapper">',
       '#suffix' => '</div>',
diff -u b/core/modules/system/tests/modules/form_test/src/Form/FormTestMachineNameValidationForm.php b/core/modules/system/tests/modules/form_test/src/Form/FormTestMachineNameValidationForm.php
--- b/core/modules/system/tests/modules/form_test/src/Form/FormTestMachineNameValidationForm.php
+++ b/core/modules/system/tests/modules/form_test/src/Form/FormTestMachineNameValidationForm.php
@@ -76,7 +76,7 @@
       '#required' => TRUE,
       '#ajax' => [
         'callback' => '::buildAjaxSnackConfigureForm',
-        'wrapper_selector' => '#snack-config-form',
+        'selector' => '#snack-config-form',
         'method' => 'replace',
         'effect' => 'fade',
       ],
diff -u b/core/modules/system/tests/modules/form_test/src/Form/FormTestTableSelectFormBase.php b/core/modules/system/tests/modules/form_test/src/Form/FormTestTableSelectFormBase.php
--- b/core/modules/system/tests/modules/form_test/src/Form/FormTestTableSelectFormBase.php
+++ b/core/modules/system/tests/modules/form_test/src/Form/FormTestTableSelectFormBase.php
@@ -40,7 +40,7 @@
       '#empty' => t('Empty text.'),
       '#ajax' => [
         'callback' => 'form_test_tableselect_ajax_callback',
-        'wrapper_selector' => '#tableselect-wrapper',
+        'selector' => '#tableselect-wrapper',
       ],
     ];
 
diff -u b/core/modules/system/tests/modules/js_ajax_test/src/Form/JsAjaxTestForm.php b/core/modules/system/tests/modules/js_ajax_test/src/Form/JsAjaxTestForm.php
--- b/core/modules/system/tests/modules/js_ajax_test/src/Form/JsAjaxTestForm.php
+++ b/core/modules/system/tests/modules/js_ajax_test/src/Form/JsAjaxTestForm.php
@@ -40,7 +40,7 @@
           'type' => 'throbber',
           'message' => NULL,
         ],
-        'wrapper_selector' => '#js_ajax_test_form_wrapper',
+        'selector' => '#js_ajax_test_form_wrapper',
       ],
     ];
     return $form;
diff -u b/core/modules/system/tests/modules/js_webassert_test/src/Form/JsWebAssertTestForm.php b/core/modules/system/tests/modules/js_webassert_test/src/Form/JsWebAssertTestForm.php
--- b/core/modules/system/tests/modules/js_webassert_test/src/Form/JsWebAssertTestForm.php
+++ b/core/modules/system/tests/modules/js_webassert_test/src/Form/JsWebAssertTestForm.php
@@ -38,7 +38,7 @@
           'type' => 'throbber',
           'message' => NULL,
         ],
-        'wrapper_selector' => '#js_webassert_test_form_wrapper',
+        'selector' => '#js_webassert_test_form_wrapper',
       ],
     ];
     // Button to test for the waitForLink() assertion.
@@ -52,7 +52,7 @@
           'type' => 'throbber',
           'message' => NULL,
         ],
-        'wrapper_selector' => '#js_webassert_test_form_wrapper',
+        'selector' => '#js_webassert_test_form_wrapper',
       ],
     ];
     // Button to test for the waitForField() assertion.
@@ -66,7 +66,7 @@
           'type' => 'throbber',
           'message' => NULL,
         ],
-        'wrapper_selector' => '#js_webassert_test_form_wrapper',
+        'selector' => '#js_webassert_test_form_wrapper',
       ],
     ];
     // Button to test for the waitForId() assertion.
@@ -80,7 +80,7 @@
           'type' => 'throbber',
           'message' => NULL,
         ],
-        'wrapper_selector' => '#js_webassert_test_form_wrapper',
+        'selector' => '#js_webassert_test_form_wrapper',
       ],
     ];
 
@@ -95,7 +95,7 @@
           'type' => 'throbber',
           'message' => NULL,
         ],
-        'wrapper_selector' => '#js_webassert_test_form_wrapper',
+        'selector' => '#js_webassert_test_form_wrapper',
       ],
     ];
 
@@ -110,7 +110,7 @@
           'type' => 'throbber',
           'message' => NULL,
         ],
-        'wrapper_selector' => '#js_webassert_test_form_wrapper',
+        'selector' => '#js_webassert_test_form_wrapper',
       ],
     ];
     return $form;
diff -u b/core/modules/views_ui/admin.inc b/core/modules/views_ui/admin.inc
--- b/core/modules/views_ui/admin.inc
+++ b/core/modules/views_ui/admin.inc
@@ -54,7 +54,7 @@
   // to request so that the wrapper can be recognized by the AJAX system and
   // its content can be dynamically updated. So instead, we will keep track of
   // duplicate IDs (within a single request) on our own, later in this function.
-  $triggering_element['#ajax']['wrapper_selector'] = '#edit-view-' . implode('-', $refresh_parents) . '-wrapper';
+  $triggering_element['#ajax']['selector'] = '#edit-view-' . implode('-', $refresh_parents) . '-wrapper';
 
   // Add a submit button for users who do not have JavaScript enabled. It
   // should be displayed next to the triggering element on the form.
@@ -107,11 +107,11 @@
   // Attach custom data to the triggering element and submit button, so we can
   // use it in both the process function and AJAX callback.
   $ajax_data = [
-    'wrapper_selector' => $triggering_element['#ajax']['wrapper_selector'],
+    'selector' => $triggering_element['#ajax']['selector'],
     'trigger_key' => $trigger_key,
     'refresh_parents' => $refresh_parents,
   ];
-  $seen_ids[$triggering_element['#ajax']['wrapper_selector']] = TRUE;
+  $seen_ids[$triggering_element['#ajax']['selector']] = TRUE;
   $triggering_element['#views_ui_ajax_data'] = $ajax_data;
   $wrapping_element[$button_key]['#views_ui_ajax_data'] = $ajax_data;
 }
@@ -164,7 +164,7 @@
 
   // The HTML ID that AJAX expects was also stored in a property on the
   // element, so use that information to insert the wrapper <div> here.
-  $id = substr($element['#views_ui_ajax_data']['wrapper_selector'], 1);
+  $id = substr($element['#views_ui_ajax_data']['selector'], 1);
   $refresh_element += [
     '#prefix' => '',
     '#suffix' => '',
diff -u b/core/modules/views_ui/js/ajax.es6.js b/core/modules/views_ui/js/ajax.es6.js
--- b/core/modules/views_ui/js/ajax.es6.js
+++ b/core/modules/views_ui/js/ajax.es6.js
@@ -245,7 +245,7 @@
             return true;
           }
 
-          elementSettings.wrapper_selector = '.views-preview-wrapper';
+          elementSettings.selector = '.views-preview-wrapper';
           elementSettings.method = 'replaceWith';
           elementSettings.base = $(this).attr('id');
           elementSettings.element = this;
@@ -273,7 +273,7 @@
             return true;
           }
 
-          elementSettings.wrapper_selector = '.views-preview-wrapper';
+          elementSettings.selector = '.views-preview-wrapper';
           elementSettings.method = 'replaceWith';
           elementSettings.event = 'click';
           elementSettings.base = $(this).attr('id');
diff -u b/core/modules/views_ui/js/ajax.js b/core/modules/views_ui/js/ajax.js
--- b/core/modules/views_ui/js/ajax.js
+++ b/core/modules/views_ui/js/ajax.js
@@ -113,7 +113,7 @@
           return true;
         }
 
-        elementSettings.wrapper_selector = '.views-preview-wrapper';
+        elementSettings.selector = '.views-preview-wrapper';
         elementSettings.method = 'replaceWith';
         elementSettings.base = $(this).attr('id');
         elementSettings.element = this;
@@ -132,7 +132,7 @@
           return true;
         }
 
-        elementSettings.wrapper_selector = '.views-preview-wrapper';
+        elementSettings.selector = '.views-preview-wrapper';
         elementSettings.method = 'replaceWith';
         elementSettings.event = 'click';
         elementSettings.base = $(this).attr('id');
diff -u b/core/modules/views_ui/src/ViewPreviewForm.php b/core/modules/views_ui/src/ViewPreviewForm.php
--- b/core/modules/views_ui/src/ViewPreviewForm.php
+++ b/core/modules/views_ui/src/ViewPreviewForm.php
@@ -87,7 +87,7 @@
         '#id' => 'preview-submit',
         '#ajax' => [
           'url' => Url::fromRoute('entity.view.preview_form', ['view' => $view->id(), 'display_id' => $this->displayID]),
-          'wrapper_selector' => '.views-preview-wrapper',
+          'selector' => '.views-preview-wrapper',
           'event' => 'click',
           'progress' => ['type' => 'fullscreen'],
           'method' => 'replaceWith',
diff -u b/core/tests/Drupal/Tests/Core/Render/Element/RenderElementTest.php b/core/tests/Drupal/Tests/Core/Render/Element/RenderElementTest.php
--- b/core/tests/Drupal/Tests/Core/Render/Element/RenderElementTest.php
+++ b/core/tests/Drupal/Tests/Core/Render/Element/RenderElementTest.php
@@ -72,17 +72,17 @@
    */
   public function providerTestPreRenderAjaxForm() {
     $data = [];
-    $data['wrapper_selector'] = [
+    $data['selector'] = [
       [
         '#type' => 'select',
         '#id' => 'test',
         '#ajax' => [
-          'wrapper_selector' => '#foo',
+          'selector' => '#foo',
           'callback' => 'test-callback',
         ],
       ],
       [
-        'wrapper_selector' => '#foo',
+        'selector' => '#foo',
         'callback' => 'test-callback',
         'event' => 'change',
         'url' => '/test?foo=bar&ajax_form=1',
@@ -90,7 +90,7 @@
       ],
       '/test?foo=bar&ajax_form=1',
     ];
-    // @todo Remove support for 'wrapper' and solely use 'wrapper_selector'.
+    // @todo Remove support for 'wrapper' and solely use 'selector'.
     $data['wrapper'] = [
       [
         '#type' => 'select',
@@ -103,7 +103,7 @@
       [
         'callback' => 'test-callback',
         'event' => 'change',
-        'wrapper_selector' => '#foo',
+        'selector' => '#foo',
         'url' => '/test?foo=bar&ajax_form=1',
         'dialogType' => 'ajax',
       ],
@@ -132,7 +132,7 @@
       '#type' => 'select',
       '#id' => 'test',
       '#ajax' => [
-        'wrapper_selector' => '#foo',
+        'selector' => '#foo',
         'callback' => 'test-callback',
         'options' => [
           'query' => [