Machine that produces useful energy of motion from some other form of energy. The term is usually restricted to combustion engines, which burn fuel. These machines include the steam engine
, diesel engine
, jet engine
, and rocket
engine. Such engines are distinguished from electric motors which, in providing their power, do not directly alter the chemical or physical composition of a substance. Combustion engines are of two main kinds: an external
combustion engine burns its fuel outside the chamber in which motion is produced. In a steam locomotive
, for example, the fire box is separate from the cylinders. An internal combustion engine
burns its fuel and develops motion in the same place.
en·gine / ˈenjən/ •
n. 1. a machine with moving parts that converts power into motion. ∎ a thing that is the agent or instrument of a particular process: exports used to be the engine of growth.2. a railroad locomotive. ∎ hist. a mechanical device or instrument, esp. one used in warfare: a siege engine.DERIVATIVES: en·gined adj. [in comb.] a twin-engined helicopter.
†contrivance, artifice XIII; †ingenuity, genius XIV; B.
machine of war XIII; mechanical contrivance XIV; complex machine (later spec. as source of power) XVII. — OF. engin
:- L. ingenium
natural quality or disposition, talents, genius, clever device.