Add :term:s for iterator.
diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst
index e150070..c1bffa4 100644
--- a/Doc/library/itertools.rst
+++ b/Doc/library/itertools.rst
@@ -10,7 +10,7 @@
 
 .. versionadded:: 2.3
 
-This module implements a number of iterator building blocks inspired by
+This module implements a number of :term:`iterator` building blocks inspired by
 constructs from the Haskell and SML programming languages.  Each has been recast
 in a form suitable for Python.