burial vs entombment

burial and entombment both are nouns.

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

As nouns, burial and entombment are synonyms defined as:

Other synonyms of burial include inhumation, interment, sepulture.

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