dead room vs crematory

dead room and crematory both are nouns.

Word	Noun	Adjective	Verb	Adverb
dead room	Yes	No	No	No
crematory	Yes	No	No	No

As nouns, crematory is a hyponym of dead room; that is, crematory is a word with a more specific, narrower meaning than dead room:

dead room: a building (or room) where dead bodies are kept before burial or cremation
crematory: a mortuary where corpses are cremated

dead room (noun)	crematory (noun)
a building (or room) where dead bodies are kept before burial or cremation	a furnace where a corpse can be burned and reduced to ashes
	a mortuary where corpses are cremated