diff --git a/c3l_membership/forms.py b/c3l_membership/forms.py
--- a/c3l_membership/forms.py
+++ b/c3l_membership/forms.py
@@ -124,7 +124,7 @@ class MembershipForm(FlaskForm):
         validators=[Optional(), Length(max=4000)],
     )
 
-    zip = StringField(
+    postal = StringField(
         lazy_gettext("Postal Code"),
         validators=[Optional(), Length(max=30)],
     )