ramjet engine vs jet engine

ramjet engine and jet engine both are nouns.

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

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

ramjet engine: a simple type of jet engine; must be launched at high speed
jet engine: a gas turbine produces a stream of hot gas that propels a jet plane by reaction propulsion

ramjet engine (noun)	jet engine (noun)
a simple type of jet engine; must be launched at high speed	a gas turbine produces a stream of hot gas that propels a jet plane by reaction propulsion