sepulture vs mausoleum

sepulture and mausoleum both are nouns.

Word	Noun	Adjective	Verb	Adverb
sepulture	Yes	No	No	No
mausoleum	Yes	No	No	No

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

Other hyponyms of sepulture include crypt, monument, repository, burial vault, vault.

sepulture (noun)	mausoleum (noun)
a chamber that is used as a grave	a large burial chamber, usually above ground
the ritual placing of a corpse in a grave