Noun

1. An open-mouthed bar at the end of a car, which receives a coupling link and pin by which the car is drawn. It is usually provided with a spring to give elasticity to the connection between the cars of a train.
2. A bar of iron with an eye at each end, or a heavy link, for coupling a locomotive to a tender or car.
3. (road transport) A device to couple a powered road vehicle to a load to transfer tractive effort to the load, either as a push or as a pull. (See also Wikipedia:Drawbar)
4. A device invented originally by Hammond for installation in its organs
5. A device for changing the tools on milling machines