ramjet engine vs ramjet

ramjet engine and ramjet both are nouns.

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

As nouns, ramjet engine and ramjet are synonyms defined as:

ramjet engine and ramjet: a simple type of jet engine; must be launched at high speed

Other synonyms of ramjet engine include atherodyde, athodyd, flying drainpipe.

ramjet engine (noun)	ramjet (noun)
a simple type of jet engine; must be launched at high speed	a simple type of jet engine; must be launched at high speed