Relating to or allowing the operation of engines or the movement of vehicles in a direction opposite to the usual or predominant direction. Cf. re…

Esp. of an engine: having a throttle; controlled by means of a throttle.

Physics and Chemistry. Thermodynamics. Designating a change or process that is capable of reversal, completely and in detail; (strictly) denoting…

Esp. of an engine: having several cylinders. Of a vehicle: having such an engine.

= multi-cylinder, adj.

= four-stroke, adj.

= multi-cylinder, adj.

Of an engine: free from knock (knock, n.1 1c).

That can be controlled by means of a throttle; spec. (of a rocket engine) capable of having the thrust varied.

Capable of running on or burning more than one kind of fuel.

Of an aircraft, engine, etc.: increased in size or operating capacity; based on a smaller or less powerful design. Cf. stretch, v. 21e.

= multi-fuel, adj.