elevator vs dumbwaiter

elevator and dumbwaiter both are nouns.

Word	Noun	Adjective	Verb	Adverb
elevator	Yes	No	No	No
dumbwaiter	Yes	No	No	No

As nouns, dumbwaiter is a hyponym of elevator; that is, dumbwaiter is a word with a more specific, narrower meaning than elevator:

elevator: lifting device consisting of a platform or cage that is raised and lowered mechanically in a vertical shaft in order to move people from one floor to another in a building
dumbwaiter: a small elevator used to convey food (or other goods) from one floor of a building to another

Other hyponyms of elevator include food elevator, freight elevator, service elevator, paternoster.

elevator (noun)	dumbwaiter (noun)
lifting device consisting of a platform or cage that is raised and lowered mechanically in a vertical shaft in order to move people from one floor to another in a building	a small elevator used to convey food (or other goods) from one floor of a building to another
the airfoil on the tailplane of an aircraft that makes it ascend or descend