engine (n.) Look up engine at Dictionary.com
c.1300, "mechanical device," especially one used in war; "manner of construction," also "skill, craft, innate ability; deceitfulness, trickery," from Old French engin "skill, wit, cleverness," also "trick, deceit, stratagem; war machine" (12c.), from Latin ingenium "inborn qualities, talent" (see ingenious), in Late Latin "a war engine, battering ram." Sense of "device that converts energy to mechanical power" is 18c.; in 19c. especially of steam engines.