builtin -> built-in.
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index 8616d5d..0005792 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -816,7 +816,7 @@
 
    ``'c_call'``
       A C function is about to be called.  This may be an extension function or
-      a builtin.  *arg* is the C function object.
+      a built-in.  *arg* is the C function object.
 
    ``'c_return'``
       A C function has returned. *arg* is ``None``.