Definition of: engine

(en′jin) noun
1. A machine by which energy is applied to the doing of work, notably one that converts heat energy into mechanical work: a steam engine, gas engine, etc.
2. A locomotive, taken as a whole.
3. Any large mechanism or material contrivance for producing some effect, especially of destruction or disintegration: an engine of war.
4. Any agency or instrumentality designedly employed. [<OF engin <L ingenium <in- in + gen-, root of gignere beget]