A PDL (page description language) is a trademark and technology developed by Adobe Systems and used with computer printers and imagesetters to define how to print a page properly. Today, PostScript has become the de facto standard method of printing in desktop publishing.
Those interested in doing PostScript programming should get the blue book PostScript Language Tutorial and CookBook.
What is a PostScript clone?
Software program designed to impersonate Adobe PostScript. While similar, a PostScript clone may not produce the same quality text and images.