diff --git a/doc/src/sgml/ref/create_domain.sgml b/doc/src/sgml/ref/create_domain.sgml
index 81a89249260..e4b856d630c 100644
--- a/doc/src/sgml/ref/create_domain.sgml
+++ b/doc/src/sgml/ref/create_domain.sgml
@@ -94,7 +94,8 @@ CREATE DOMAIN name [ AS ]
An optional collation for the domain. If no collation is
- specified, the underlying data type's default collation is used.
+ specified, the domain has the same collation behavior as its
+ underlying data type.
The underlying type must be collatable if COLLATE
is specified.