REACTION MOTOR

an engine which expels a stream of matter at high velocity, the reaction from which creates a forward accelerating force; a jet engine. —9th ACC Volume 3 Approved Glossary

n.a type of engine which expels a stream of burned exhaust gases at a high velocity, the reaction from which creates thrust or forward accelerating force (i.e., it causes the engine to move forward). Jet or rocket engines are reaction motors.