monument vs burial chamber

monument and burial chamber both are nouns.

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

As nouns, burial chamber is a hypernym of monument; that is, burial chamber is a word with a broader meaning than monument:

Other hypernyms of monument include sepulcher, sepulchre, sepulture.

monument (noun)	burial chamber (noun)
a structure erected to commemorate persons or events	a chamber that is used as a grave
a burial vault (usually for some famous person)
an important site that is marked and preserved as public property