rocket engine vs jet engine

rocket engine and jet engine both are nouns.

Word	Noun	Adjective	Verb	Adverb
rocket engine	Yes	No	No	No
jet engine	Yes	No	No	No

As nouns, jet engine is a hypernym of rocket engine; that is, jet engine is a word with a broader meaning than rocket engine:

rocket engine: a jet engine containing its own propellant and driven by reaction propulsion
jet engine: a gas turbine produces a stream of hot gas that propels a jet plane by reaction propulsion

rocket engine (noun)	jet engine (noun)
a jet engine containing its own propellant and driven by reaction propulsion	a gas turbine produces a stream of hot gas that propels a jet plane by reaction propulsion