The core section of a building from which corridors extend.

An electric socket in a plugboard into which one may insert or connect leads or may plug wires.

1. The cylindrical central part of a wheel, propeller, or fan.

2. A piece in a lock that is turned by the knob spindle, causing the bolt to move.

3. A short coupling that joins plumbing pipes.

In surveying, a stake that marks the position of a theodolite.

A steel punch used in making a working die for a coin or medal.