builtin -> built-in.
diff --git a/Doc/library/weakref.rst b/Doc/library/weakref.rst
index 2ca864f..5dcb030 100644
--- a/Doc/library/weakref.rst
+++ b/Doc/library/weakref.rst
@@ -65,7 +65,7 @@
.. versionchanged:: 2.4
Added support for files, sockets, arrays, and patterns.
-Several builtin types such as :class:`list` and :class:`dict` do not directly
+Several built-in types such as :class:`list` and :class:`dict` do not directly
support weak references but can add support through subclassing::
class Dict(dict):