: Peer-to-peer :

A communications environment that allows all desktop and laptop computers in the network to act as servers and share their files with all other users on the network. Peer-to-peer networks are quite common in small offices that do not use a dedicated file server. In such cases, only specific folders are generally made sharable in each machine, not the entire hard disk.

Peer-to-peer networks also exist on the Internet that allow users to have access to other users' files residing on their hard disks. This type of sharing was popularized by the now-defunct Napster music service.