Normalize spelling of Mac OS X.
diff --git a/Doc/library/os.path.rst b/Doc/library/os.path.rst
index bc2220d..01406e0 100644
--- a/Doc/library/os.path.rst
+++ b/Doc/library/os.path.rst
@@ -190,9 +190,9 @@
 
 .. function:: normcase(path)
 
-   Normalize the case of a pathname.  On Unix and MacOSX, this returns the path unchanged; on
-   case-insensitive filesystems, it converts the path to lowercase.  On Windows, it
-   also converts forward slashes to backward slashes.
+   Normalize the case of a pathname.  On Unix and Mac OS X, this returns the
+   path unchanged; on case-insensitive filesystems, it converts the path to
+   lowercase.  On Windows, it also converts forward slashes to backward slashes.
 
 
 .. function:: normpath(path)
diff --git a/Doc/library/ttk.rst b/Doc/library/ttk.rst
index f38664e..1795771 100644
--- a/Doc/library/ttk.rst
+++ b/Doc/library/ttk.rst
@@ -656,7 +656,7 @@
 Platform-specific notes
 ^^^^^^^^^^^^^^^^^^^^^^^
 
-* On MacOS X, toplevel windows automatically include a built-in size grip
+* On Mac OS X, toplevel windows automatically include a built-in size grip
   by default. Adding a :class:`Sizegrip` is harmless, since the built-in
   grip will just mask the widget.