What is an "executable crack" in terms of downloading torrent?

A crack program can either be used as a separate launcher of a particular program, or can be run once to alter the code of the launcher that already exists. Most commonly with torrents, the crack is designed to remove certain aspects of a game or program that would prevent a torrenter from using it, like entering your CD-Key or going through some kind of online registration. Cracks allow you to byp these steps, and get you towards playing or using what you downloaded.