burial chamber vs sepulcher

burial chamber and sepulcher both are nouns.

Word	Noun	Adjective	Verb	Adverb
burial chamber	Yes	No	No	No
sepulcher	Yes	No	No	No

As nouns, burial chamber and sepulcher are synonyms defined as:

Other synonyms of burial chamber include sepulchre, sepulture.

burial chamber (noun)	sepulcher (noun)
a chamber that is used as a grave	a chamber that is used as a grave