en·gine 
(ĕnjĭn)
(ĕnjĭn)n.
1.
a. A machine that converts energy into mechanical force or motion.
b. Such a machine distinguished from an electric, spring-driven, or hydraulic motor by its use of a fuel.
2.
a. A mechanical appliance, instrument, or tool: engines of war.
b. An agent, instrument, or means of accomplishment.
3. A locomotive.
4. A fire engine.
5. Computers A search engine.
tr.v. en·gined, en·gin·ing, en·gines
To equip with an engine or engines.
[Middle English engin, skill, machine, from Old French, innate ability, from Latin ingenium; see genə- in the Appendix of Indo-European roots.]