entombment vs burial

entombment and burial both are nouns.

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

As nouns, entombment and burial are synonyms defined as:

Other synonyms of entombment include inhumation, interment, sepulture.

entombment (noun)	burial (noun)
the ritual placing of a corpse in a grave	concealing something under the ground
	the ritual placing of a corpse in a grave