Sockets

noun

1. An opening into which a plug or other connecting part is designed to fit (e.g. a light bulb socket).
2. A hollow into a bone which a part fits, such as an eye, or another bone, in the case of a joint.
3. One endpoint of a two-way communication link, used for interprocess communication across a network.
4. One endpoint of a two-way named pipe on Unix and Unix-like systems, used for interprocess communication.
5. A hollow tool for grasping and lifting tools dropped in a well-boring.