A wall plug; a screw anchor.
An opening into which a plug or other connecting part is designed to fit (e.g. a light bulb socket).
One endpoint of a two-way communication link, used for interprocess communication across a network.
A hollow into a bone which a part fits, such as an eye, or another bone, in the case of a joint.
A hollow tool for grasping and lifting tools dropped in a well-boring.
One endpoint of a two-way named pipe on Unix and Unix-like systems, used for interprocess communication.
The hollow of a candlestick.
A steel apparatus attached to a saddle to protect the thighs and legs.
To place or fit in a socket.