diff --git a/src/wp-admin/includes/class-wp-terms-list-table.php b/src/wp-admin/includes/class-wp-terms-list-table.php
index b710c5f630..7d8f8bfe5e 100644
--- a/src/wp-admin/includes/class-wp-terms-list-table.php
+++ b/src/wp-admin/includes/class-wp-terms-list-table.php
@@ -11,6 +11,8 @@ class WP_Terms_List_Table extends WP_List_Table {
 
 	public $callback_args;
 
+	private $level;
+
 	/**
 	 * Constructor.
 	 *