diff --git a/lib/Minilisp.pm b/lib/Minilisp.pm
index a20f5b9..41be544 100644
--- a/lib/Minilisp.pm
+++ b/lib/Minilisp.pm
@@ -125,7 +125,7 @@ sub ctx_get {
       $ctx = $ctx->{base};
     }
 
-  die "Variable $identifier does not defined" unless defined $ctx;
+  die "Identifier $identifier is not defined" unless defined $ctx;
 
   return $ctx->{vars}->{$identifier};
 }