diff --git a/Lib/lib-old/packmail.py b/Lib/lib-old/packmail.py
index a964d6d11b4..2ff067d0c20 100644
--- a/Lib/lib-old/packmail.py
+++ b/Lib/lib-old/packmail.py
@@ -21,7 +21,7 @@ def pack(outfp, file, name):
 def packsome(outfp, dirname, names):
 	for name in names:
 		print name
-		file = macpath.cat(dirname, name)
+		file = macpath.join(dirname, name)
 		pack(outfp, file, name)
 
 # Pack all files from a directory
@@ -33,13 +33,13 @@ def packall(outfp, dirname):
 # Pack all files from a directory that are not older than a give one
 def packnotolder(outfp, dirname, oldest):
 	names = mac.listdir(dirname)
-	oldest = macpath.cat(dirname, oldest)
+	oldest = macpath.join(dirname, oldest)
 	st = mac.stat(oldest)
 	mtime = st[ST_MTIME]
 	todo = []
 	for name in names:
 		print name, '...',
-		st = mac.stat(macpath.cat(dirname, name))
+		st = mac.stat(macpath.join(dirname, name))
 		if st[ST_MTIME] >= mtime:
 			print 'Yes.'
 			todo.append(name)
@@ -55,7 +55,7 @@ def packtree(outfp, dirname):
 	names = mac.listdir(dirname)
 	subdirs = []
 	for name in names:
-		fullname = macpath.cat(dirname, name)
+		fullname = macpath.join(dirname, name)
 		if macpath.isdir(fullname):
 			subdirs.append(fullname)
 		else:
diff --git a/Lib/macpath.py b/Lib/macpath.py
index 99254abce03..58cbb88e500 100644
--- a/Lib/macpath.py
+++ b/Lib/macpath.py
@@ -15,11 +15,11 @@ def isabs(s):
 	return ':' in s and s[0] <> ':'
 
 
-# Concatenate two pathnames.
+# Join two pathnames.
 # The result is equivalent to what the second pathname would refer to
 # if the first pathname were the current directory.
 
-def cat(s, t):
+def join(s, t):
 	if (not s) or isabs(t): return t
 	if t[:1] = ':': t = t[1:]
 	if ':' not in s:
@@ -29,9 +29,12 @@ def cat(s, t):
 	return s + t
 
 
+cat = join # For compatibility
+
+
 # Split a pathname in two parts: the directory leading up to the final bit,
 # and the basename (the filename, without colons, in that directory).
-# The result (s, t) is such that cat(s, t) yields the original argument.
+# The result (s, t) is such that join(s, t) yields the original argument.
 
 def split(s):
 	if ':' not in s: return '', s
diff --git a/Lib/packmail.py b/Lib/packmail.py
index a964d6d11b4..2ff067d0c20 100644
--- a/Lib/packmail.py
+++ b/Lib/packmail.py
@@ -21,7 +21,7 @@ def pack(outfp, file, name):
 def packsome(outfp, dirname, names):
 	for name in names:
 		print name
-		file = macpath.cat(dirname, name)
+		file = macpath.join(dirname, name)
 		pack(outfp, file, name)
 
 # Pack all files from a directory
@@ -33,13 +33,13 @@ def packall(outfp, dirname):
 # Pack all files from a directory that are not older than a give one
 def packnotolder(outfp, dirname, oldest):
 	names = mac.listdir(dirname)
-	oldest = macpath.cat(dirname, oldest)
+	oldest = macpath.join(dirname, oldest)
 	st = mac.stat(oldest)
 	mtime = st[ST_MTIME]
 	todo = []
 	for name in names:
 		print name, '...',
-		st = mac.stat(macpath.cat(dirname, name))
+		st = mac.stat(macpath.join(dirname, name))
 		if st[ST_MTIME] >= mtime:
 			print 'Yes.'
 			todo.append(name)
@@ -55,7 +55,7 @@ def packtree(outfp, dirname):
 	names = mac.listdir(dirname)
 	subdirs = []
 	for name in names:
-		fullname = macpath.cat(dirname, name)
+		fullname = macpath.join(dirname, name)
 		if macpath.isdir(fullname):
 			subdirs.append(fullname)
 		else:
diff --git a/Mac/Lib/maccache.py b/Mac/Lib/maccache.py
index dc6502bda1c..47b673cf39a 100644
--- a/Mac/Lib/maccache.py
+++ b/Mac/Lib/maccache.py
@@ -25,7 +25,7 @@ FILE = 1
 LISTTYPE = type([])
 
 def _stat(name):
-	name = macpath.cat(cwd, name)
+	name = macpath.join(cwd, name)
 	if cache.has_key(name):
 		return cache[name]
 	if macpath.isfile(name):