[en-juh
n] 
| 1. | a machine for converting thermal energy into mechanical energy or power to produce force and motion. |
| 2. | a railroad locomotive. |
| 3. | a fire engine. |
| 4. | any mechanical contrivance. |
| 5. | a machine or instrument used in warfare, as a battering ram, catapult, or piece of artillery. |
| 6. | Obsolete. an instrument of torture, esp. the rack. |
| en·gine (ěn'jĭn) n.
To equip with an engine or engines. [Middle English engin, skill, machine, from Old French, innate ability, from Latin ingenium; see genə- in Indo-European roots.] |
engine jargon
1. A piece of hardware that encapsulates some function but can't be used without some kind of front end. Today we have, especially, "print engine": the guts of a laser printer.
2. An analogous piece of software; notionally, one that does a lot of noisy crunching, such as a "database engine", or "search engine".
The hackish senses of "engine" are actually close to its original, pre-Industrial-Revolution sense of a skill, clever device, or instrument (the word is cognate to "ingenuity"). This sense had not been completely eclipsed by the modern connotation of power-transducing machinery in Charles Babbage's time, which explains why he named the stored-program computer that he designed in 1844 the "Analytical Engine".
[The Jargon File]
(1996-05-31)