Longman Dictionary of Contemporary English
Wiktionary
n. 1 Propulsion that is caused by the expulsion of a jet of fluid, especially by a jet engine 2 The study of devices propelled by jet propulsion
WordNet
n. propulsion by means of the discharge of a jet of fluid toward the rear
Wikipedia
Jet propulsion is thrust produced by passing a jet of matter (typically air or water) in the opposite direction to the direction of motion. By Newton's third law, the moving body is propelled in the opposite direction to the jet. It is most commonly used in the jet engine, but is also the most common means of spacecraft propulsion.
A number of animals, including cephalopods, sea hares, arthropods, and fish have convergently evolved jet propulsion mechanisms.
Usage examples of "jet propulsion".
Egan had finally begun to relax after satisfying himself that his huge magnetic water jet propulsion engines were operating efficiently and without problems.
Normally, if it comes from somewhere like the Jet Propulsion Lab or the National Institutes of Health, it should be reliable.
It was a miracle he'd made it up the arroyo to the Jet Propulsion Laboratory parking lot and got the Porsche into the tiny slot the JPL guard had showed him.
So I'm out at the Jet Propulsion Laboratory where the pictures come in.