diff --git a/css-namespaces-3/Overview.bs b/css-namespaces-3/Overview.bs
index 9442ce15f4a..4c9a0625421 100644
--- a/css-namespaces-3/Overview.bs
+++ b/css-namespaces-3/Overview.bs
@@ -150,7 +150,7 @@ Syntax</h3>
 	<pre>
 		@namespace <<namespace-prefix>>? [ <<string>> | <<url>> ] ;
 
-		<dfn>&lt;namespace-prefix&gt;</dfn> = <<ident>>
+		<dfn>&lt;namespace-prefix&gt;</dfn> = <<custom-ident>>
 	</pre>
 
 	Any ''@namespace'' rules must follow all @charset and @import rules