diff --git a/src/wp-includes/post.php b/src/wp-includes/post.php
index 7073328c0d..fb90f626f4 100644
--- a/src/wp-includes/post.php
+++ b/src/wp-includes/post.php
@@ -3823,7 +3823,14 @@ function wp_get_recent_posts( $args = array(), $output = ARRAY_A ) {
  *     @type int[]  $post_category         Array of category IDs.
  *                                         Defaults to value of the 'default_category' option.
  *     @type array  $tags_input            Array of tag names, slugs, or IDs. Default empty.
- *     @type array  $tax_input             Array of taxonomy terms keyed by their taxonomy name. Default empty.
+ *     @type array  $tax_input             An array of taxonomy terms keyed by their taxonomy name.
+ *                                         If the taxonomy is hierarchical, the term list needs to be
+ *                                         either an array of term IDs or a comma-separated string of IDs.
+ *                                         If the taxonomy is non-hierarchical, the term list can be an array
+ *                                         that contains term names or slugs, or a comma-separated string
+ *                                         of names or slugs. This is because, in hierarchical taxonomy,
+ *                                         child terms can have the same names with different parent terms,
+ *                                         so the only way to connect them is using ID. Default empty.
  *     @type array  $meta_input            Array of post meta values keyed by their post meta key. Default empty.
  * }
  * @param bool  $wp_error         Optional. Whether to return a WP_Error on failure. Default false.