donkey engine

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A small auxiliary steam engine used for hoisting or pumping, especially aboard ship.
2. n. A small locomotive.

Century Dictionary and Cyclopedia

1. n. In machinery, a small steam-engine used where great power is not required, and often to perform some subsidiary operation. Donkey-engines on steam-vessels, etc., are used for pumping water into the boilers or from the hold, handling the cargo, hoisting the anchor or the sails, etc.

GNU Webster's 1913

1. n. a small auxiliary engine not used for propelling, but for pumping water into the boilers, raising heavy weights, and like purposes.

WordNet 3.0

1. n. (nautical) a small engine (as one used on board ships to operate a windlass)
2. n. a locomotive for switching rolling stock in a railroad yard