diff --git a/src/ol/overlay.js b/src/ol/overlay.js
index 7d2327f6f8..d9b1ec15b9 100644
--- a/src/ol/overlay.js
+++ b/src/ol/overlay.js
@@ -51,7 +51,8 @@ ol.OverlayPositioning = {
 
 /**
  * @classdesc
- * Like {@link ol.control.Control}, Overlays are visible widgets.
+ * An element to be displayed over the map and attached to a single map
+ * location.  Like {@link ol.control.Control}, Overlays are visible widgets.
  * Unlike Controls, they are not in a fixed position on the screen, but are tied
  * to a geographical coordinate, so panning the map will move an Overlay but not
  * a Control.