diff --git a/modules/block/block.module b/modules/block/block.module
index e0cb691..bf83f75 100644
--- a/modules/block/block.module
+++ b/modules/block/block.module
@@ -633,14 +633,14 @@ function block_theme_initialize($theme) {
* The name of a region.
*
* @return
- * An array of block objects, indexed with module_delta.
- * If you are displaying your blocks in one or two sidebars, you may check
- * whether this array is empty to see how many columns are going to be
- * displayed.
+ * An array of block objects, indexed with the module name and block delta
+ * concatenated with an underscore, thus: MODULE_DELTA. If you are displaying
+ * your blocks in one or two sidebars, you may check whether this array is
+ * empty to see how many columns are going to be displayed.
*
* @todo
* Now that the blocks table has a primary key, we should use that as the
- * array key instead of module_delta.
+ * array key instead of MODULE_DELTA.
*/
function block_list($region) {
$blocks = &drupal_static(__FUNCTION__);