cinerarium vs columbarium

cinerarium and columbarium both are nouns.

Word	Noun	Adjective	Verb	Adverb
cinerarium	Yes	No	No	No
columbarium	Yes	No	No	No

As nouns, cinerarium and columbarium are synonyms defined as:

cinerarium and columbarium: a niche for a funeral urn containing the ashes of the cremated dead

cinerarium (noun)	columbarium (noun)
a niche for a funeral urn containing the ashes of the cremated dead	a sepulchral vault or other structure having recesses in the walls to receive cinerary urns
	a niche for a funeral urn containing the ashes of the cremated dead
	a birdhouse for pigeons