diff --git a/core/lib/Drupal/Core/Render/Element/Select.php b/core/lib/Drupal/Core/Render/Element/Select.php
index b1e0f4a..202e13d 100644
--- a/core/lib/Drupal/Core/Render/Element/Select.php
+++ b/core/lib/Drupal/Core/Render/Element/Select.php
@@ -38,7 +38,8 @@
  *   is #required or not.
  * - #required: (optional) Whether the user needs to select an option (TRUE)
  *   or not (FALSE). Defaults to FALSE.
- * - #size: The size of the input element in characters.
+ * - #size: Number indicating the height (per line) of input element.
+ *   This property can be used to expand the element to a scrolling list.
  *
  * Usage example:
  * @code