diff --git a/lisp/net/dictionary.el b/lisp/net/dictionary.el
index f17dc160997..9c932c0c6d5 100644
--- a/lisp/net/dictionary.el
+++ b/lisp/net/dictionary.el
@@ -317,6 +317,7 @@ Otherwise, `dictionary-search' displays definitions in a *Dictionary* buffer."
                       dictionary-read-dictionary-function)
                      vals))
          (set-default-toplevel-value symbol value))
+  :initialize #'custom-initialize-changed
   :version "30.1")
 
 (defface dictionary-word-definition-face