BitTorrent (often abbreviated to \'BT\') is a protocol (a set of rules and description of how to do things) allowing you to download files quickly by allowing people downloading the file to upload (distribute) parts of it at the same time. BitTorrent is often used for distribution of very large files, very popular files and files available for free, as it is a lot cheaper, faster and more efficient to distribute files using BitTorrent than a regular download.

µTorrent is a BitTorrent client. A \'client\' in this case is a computer program that follows the rules of a protocol. For example, HTTP (HyperText Transfer Protocol) is the protocol used to download web pages and other content - like this page - and your HTTP client (or browser) is the program you use to get those web pages. Some popular browsers include Microsoft Internet Explorer, Mozilla Firefox, Safari, and Opera. To an extent, they all work the same way because they follow the same set of rules.

Just as there are multiple HTTP clients, there are multiple BitTorrent clients, and µTorrent is one such BT client.

uTorrent is a powerful and efficient BitTorrent client. Most of the features present in other BitTorrent clients are present in uTorrent, including bandwidth prioritization, scheduling, RSS auto-downloading, and Mainline DHT. Additionally, uTorrent supports the protocol encryption joint specification and peer exchange. Unlike many torrent clients, it does not hog valuable system resources--typically using less than 6MB of memory, allowing you to use the computer as if it weren\'t there at all.