BitTorrent

BitTorrent is both the name of a file sharing system and the software which first implemented it.

By default, it refers to the system, which includes both the BitTorrent protocol, the .torrent file format, the torrent tracker (server for tracking torrent connections), and possibly other elements. The term "torrent" is often used as shorthand for the files downloaded via the BitTorrent protocol; the act of either uploading or downloading such files (which usually happen simultaneously to a certain extent, due to the nature of the system) is often called "torrenting".