cremation chamber vs furnace

cremation chamber and furnace both are nouns.

Word	Noun	Adjective	Verb	Adverb
cremation chamber	Yes	No	No	No
furnace	Yes	No	No	No

As nouns, furnace is a hypernym of cremation chamber; that is, furnace is a word with a broader meaning than cremation chamber:

cremation chamber: a furnace where a corpse can be burned and reduced to ashes
furnace: an enclosed chamber in which heat is produced to heat buildings, destroy refuse, smelt or refine ores, etc.

cremation chamber (noun)	furnace (noun)
a furnace where a corpse can be burned and reduced to ashes	an enclosed chamber in which heat is produced to heat buildings, destroy refuse, smelt or refine ores, etc.