Linux ISO

Etymology
The sharing of actual Linux ISOs (disk images that contain the files necessary to set up the Linux operating system) is a legitimate use of file sharing services. Claiming to be downloading Linux ISOs was a stereotypical excuse given to a network administrator if questioned about one's heavy Internet usage.

Noun

 * 1)  An  for setting up the Linux operating system.
 * 2)  A file, typically a movie, software or pornography, shared through a peer-to-peer file sharing service such as BitTorrent in violation of copyright or licenses.