"Engine" was originally a term for any mechanical device that converts force into motion. Hence, pre-industrial weapons such as catapults, trebuchets and battering rams were called "siege engines". The word "gin," as in "cotton gin", is short for "engine." The word derives from Old French "engin", from the Latin "ingenium", which is also the root of the word "ingenious". Most mechanical devices invented during the industrial revolution were described as engines—the steam engine being a notable example.