diff --git a/eng/req/items.rst b/eng/req/items.rst
index 874ddce..6ff7dee 100644
--- a/eng/req/items.rst
+++ b/eng/req/items.rst
@@ -1938,6 +1938,9 @@ This type refines the following types:
 * :ref:`SpecTypeFunctionalRequirementItemType` through the ``functional-type``
   attribute if the value is ``function``
 
+* :ref:`SpecTypeFunctionalRequirementItemType` through the ``functional-type``
+  attribute if the value is ``interface-define-not-defined``
+
 * :ref:`SpecTypeFunctionalRequirementItemType` through the ``functional-type``
   attribute if the value is ``operational``