A machine is a piece of equipment which uses electricity or some other form of power to perform a particular task.
When a machine operates by electricity, you refer to the part of the machine that converts power into movement as the motor.
You do not use 'machine' to refer to the part of a vehicle that provides the power that makes the vehicle move. This part of a car, bus, lorry, or plane is usually called the engine.
You talk about the engine of a ship, but the motor of a small boat.
Noun | 1. | ![]() aircraft engine - the engine that powers and aircraft automobile engine - the engine that propels an automobile auxiliary engine, donkey engine - (nautical) a small engine (as one used on board ships to operate a windlass) camshaft - has cams attached to it gearing, geartrain, power train, gear, train - wheelwork consisting of a connected set of rotating gears by which force is transmitted or motion or torque is changed; "the fool got his tie caught in the geartrain" generator - engine that converts mechanical energy into electrical energy by electromagnetic induction heat engine - any engine that makes use of heat to do work motor - machine that converts other forms of energy into mechanical energy and so imparts motion reaction engine, reaction-propulsion engine - a jet or rocket engine based on a form of aerodynamic propulsion in which the vehicle emits a high-speed stream |
2. | engine - something used to achieve a purpose; "an engine of change" causal agency, causal agent, cause - any entity that produces an effect or is responsible for events or results | |
3. | ![]() choo-choo - a child's word for locomotive diesel locomotive - a locomotive driven by a diesel engine electric locomotive - a locomotive that is powered by an electric motor cowcatcher, fender, buffer, pilot - an inclined metal frame at the front of a locomotive to clear the track footplate - the platform in the cab of a locomotive on which the engineer stands to operate the controls iron horse - (c. 1840) an early term for a locomotive pilot engine - a locomotive that precedes a train to check the track self-propelled vehicle - a wheeled vehicle that carries in itself a means of propulsion shunter - a small locomotive used to move cars around but not to make trips steam locomotive - a locomotive powered by a steam engine donkey engine, switch engine - a locomotive for switching rolling stock in a railroad yard tank engine, tank locomotive - a locomotive that carries its own fuel and water; no tender is needed traction engine - steam-powered locomotive for drawing heavy loads along surfaces other than tracks railroad train, train - public transport provided by a line of railway cars coupled together and drawn by a locomotive; "express trains don't stop at Princeton Junction" | |
4. | engine - an instrument or machine that is used in warfare, such as a battering ram, catapult, artillery piece, etc.; "medieval engines of war" battering ram - a ram used to break down doors of fortified buildings arbalest, arbalist, ballista, bricole, mangonel, onager, trebuchet, trebucket, catapult - an engine that provided medieval artillery used during sieges; a heavy war engine for hurling large stones and other missiles instrument - a device that requires skill for proper use |