Editing Engine (section)

== Terminology ==
The word ''engine'' derives from  [[Old French]] {{wikt-lang|fro|engin|engin}}, from the [[Latin]] {{lang|la|ingenium}}–the root of the word {{wikt-lang|la|ingenious|ingenious}}. Pre-industrial weapons of war, such as [[catapult]]s, [[trebuchet]]s and [[battering ram]]s, were called ''[[siege engine]]s'', and knowledge of how to construct them was often treated as a military secret. The word ''gin'', as in  ''[[cotton gin]]'', is short for ''engine''.  Most mechanical devices invented during the [[Industrial Revolution]] were described as engines—the steam engine being a notable example. However, the original steam engines, such as those by [[Thomas Savery]], were not mechanical engines but pumps. In this manner, a [[fire engine]] in its original form was merely a water pump, with the engine being transported to the fire by horses.<ref>{{Cite web|title=World Wide Words: Engine and Motor|url=http://www.worldwidewords.org/articles/engine.htm|website=World Wide Words|language=en-gb|access-date=2020-04-30|archive-date=2019-04-25|archive-url=https://web.archive.org/web/20190425010153/http://www.worldwidewords.org/articles/engine.htm|url-status=live}}</ref>

In modern usage, the term ''engine'' typically describes devices, like steam engines and internal combustion engines, that burn or otherwise consume fuel to perform [[mechanical work]] by exerting a [[torque]] or linear [[force]] (usually in the form of [[thrust]]). Devices converting heat energy into motion are commonly referred to simply as ''engines''.<ref>{{cite web |title=Engine |work=Collins English Dictionary |access-date=2012-09-03 |url=http://www.collinsdictionary.com/dictionary/english/Engine |archive-date=2012-08-29 |archive-url=https://web.archive.org/web/20120829024422/http://www.collinsdictionary.com/dictionary/english/engine |url-status=live }}</ref> Examples of engines which exert a torque include the familiar automobile gasoline and diesel engines, as well as [[turboshaft]]s. Examples of engines which produce thrust include [[turbofan]]s and [[rocket]]s.

When the internal combustion engine was invented, the term ''motor'' was initially used to distinguish it from the steam engine—which was in wide use at the time, powering locomotives and other vehicles such as [[steamroller|steam rollers]]. The term ''[[wikt:motor|motor]]'' derives from the Latin verb {{Wikt-lang|la|moto#Verb|moto}} which means 'to set in motion', or 'maintain motion'. Thus a motor is a device that imparts motion.

''Motor'' and ''engine'' are interchangeable in standard English.<ref>Dictionary definitions:
* {{OED|motor}}
* {{OED|engine}}
* {{Cite Merriam-Webster|motor}}
* {{Cite Merriam-Webster|engine}}
* {{Cite Dictionary.com|motor}}
* {{Cite Dictionary.com|engine}}</ref> In some engineering jargons, the two words have different meanings, in which ''[[wikt:engine|engine]]'' is a device that [[combustion|burns]] or otherwise consumes fuel, changing its chemical composition, and a motor is a device driven by [[Electric motor|electricity]], [[pneumatic motor|air]], or [[hydraulic motor|hydraulic]] pressure, which does not change the chemical composition of its energy source.<ref>"Engine", ''McGraw-Hill Concise Encyclopedia of Science and Technology'', Third Edition, Sybil P. Parker, ed. McGraw-Hill, Inc., 1994, p. 714.</ref><ref>{{Cite web |url=http://www.worldwidewords.org/articles/engine.htm |title=World Wide Words: Engine and Motor |last=Quinion |first=Michael |website=Worldwide Words |access-date=2018-02-03 |archive-date=2019-04-25 |archive-url=https://web.archive.org/web/20190425010153/http://www.worldwidewords.org/articles/engine.htm |url-status=live }}</ref> However, [[High-power rocketry|rocketry]] uses the term [[Model rocket motor classification|rocket motor]], even though they consume fuel.

A heat engine may also serve as a ''[[wikt:prime mover|prime mover]]''—a component that transforms the flow or changes in pressure of a [[Fluid mechanics|fluid]] into [[mechanical energy]].<ref>"Prime mover", ''McGraw-Hill Concise Encyclopedia of Science and Technology'', Third Edition, Sybil P. Parker, ed. McGraw-Hill, Inc., 1994, p. 1498.</ref> An [[automobile]] powered by an internal combustion engine may make use of various motors and pumps, but ultimately all such devices derive their power from the engine. Another way of looking at it is that a motor receives power from an external source, and then converts it into mechanical energy, while an engine creates power from pressure (derived directly from the explosive force of combustion or other [[chemical]] reaction, or secondarily from the action of some such force on other substances such as air, water, or steam).<ref>{{cite book|editor-last=Goldstein|editor-first=Norm|title=The Associated Press Stylebook and Briefing on Media Law |year=2007|publisher=Basic Books|location=New York |isbn=978-0-465-00489-8|page=84|edition=42nd}}</ref>{{better source needed|reason= You are citing an Associated Press style guide? Really? Surely there is a better source.|date=February 2024}}