diff --git a/modules/system/system.api.php b/modules/system/system.api.php
index d040ab3..52ff2ea 100644
--- a/modules/system/system.api.php
+++ b/modules/system/system.api.php
@@ -1599,10 +1599,11 @@ function hook_permission() {
  *     are passed this array data in the $variables parameter.
  *   - render element: (required if "variables" not present) A string that is
  *     the name of the sole renderable element to pass to the theme function.
- *     The string represents the name of the "variable" that will hold the
- *     renderable array inside any optional preprocess or process functions.
- *     Cannot be used with the "variables" item; only one or the other, not
- *     both, can be present in a hook's info array.
+ *     The string will be the only key in the "variables" array passed to
+ *     theme, preprocess and process functions. The corresponding value
+ *     (passed to theme()) should be a renderable array. Cannot be used with
+ *     the "variables" item; only one or the other, not both, can be present
+ *     in a hook's info array.
  *   - file: The file the implementation resides in. This file will be included
  *     prior to the theme being rendered, to make sure that the function or
  *     preprocess function (as needed) is actually loaded; this makes it