diff --git a/collects/racket/private/list.rkt b/collects/racket/private/list.rkt
index 2e160cd36c..3c931e9966 100644
--- a/collects/racket/private/list.rkt
+++ b/collects/racket/private/list.rkt
@@ -126,7 +126,7 @@
 
   (define (bad-list who orig-l)
     (raise-mismatch-error who
-                          "not a propert list: "
+                          "not a proper list: "
                           orig-l))
   (define (bad-item who a orig-l)
     (raise-mismatch-error who