diff --git a/Doc/glossary.rst b/Doc/glossary.rst
index c0ca0be304ebe4..04b3a6bf5c8465 100644
--- a/Doc/glossary.rst
+++ b/Doc/glossary.rst
@@ -813,7 +813,7 @@ Glossary
       :func:`itertools.groupby`.
 
       There are several ways to create a key function.  For example. the
-      :meth:`str.lower` method can serve as a key function for case insensitive
+      :meth:`str.casefold` method can serve as a key function for case insensitive
       sorts.  Alternatively, a key function can be built from a
       :keyword:`lambda` expression such as ``lambda r: (r[0], r[2])``.  Also,
       :func:`operator.attrgetter`, :func:`operator.itemgetter`, and