Socket (noun)

1. A hollow in a bone, typically one that forms a joint with another bone.
2. A hollow in which a bulb is planted.
3. A receptacle in an electrical device into which a plug can be inserted.
4. A recess in a tool or machine part, into which another part fits.

Origin:

Middle english: from old french socquet, probably of germanic origin.

Examples:

1. The ball and socket joint in the hip allows for a wide range of motion.
2. The bulb socket in the lamp was loose.
3. He plugged the lamp into the wall socket.
4. The tool's socket was designed to fit the size of the bolt.
5. The socket on the drill was made to fit the drill bit.