entombment vs sepulture

entombment and sepulture both are nouns.

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

As nouns, entombment and sepulture are synonyms defined as:

Other synonyms of entombment include burial, inhumation, interment.

entombment (noun)	sepulture (noun)
the ritual placing of a corpse in a grave	a chamber that is used as a grave
	the ritual placing of a corpse in a grave