diff --git a/cov.el b/cov.el
index a5f40d7..8710b12 100644
--- a/cov.el
+++ b/cov.el
@@ -751,7 +751,7 @@ even if part of the line is outside any narrrowing."
       (message "No coverage data found."))))
 
 (defun cov-update ()
-  "Turn on cov-mode."
+  "Update overlays."
   (interactive)
   (cov-clear-overlays)
   (cov-set-overlays))