diff --git a/wp-includes/ms-functions.php b/wp-includes/ms-functions.php
index 3a6d7fae1..bf59db195 100644
--- a/wp-includes/ms-functions.php
+++ b/wp-includes/ms-functions.php
@@ -1703,7 +1703,16 @@ function fix_import_form_size( $size ) {
 		return $size; // default
 }
 
-/* Global Categories */
+/**
+ * Maintains a canonical list of terms by syncing terms created for each blog with the global terms table.
+ *
+ * @since 3.0.0
+ *
+ * @see term_id_filter
+ *
+ * @param int $term_id An ID for a term on the current blog.
+ * @return int An ID from the global terms table mapped from $term_id.
+ */
 function global_terms( $term_id, $deprecated = '' ) {
 	global $wpdb;