diff --git a/doc/manual/generics.txt b/doc/manual/generics.txt
index cce3a88307..2736f88fb8 100644
--- a/doc/manual/generics.txt
+++ b/doc/manual/generics.txt
@@ -219,7 +219,7 @@ Concepts are written in the following form:
       (x < y) is bool
 
     Container[T] = concept c
-      c.len is ordinal
+      c.len is Ordinal
       items(c) is iterator
       for value in c:
         type(value) is T