burial mound vs grave mound

burial mound and grave mound both are nouns.

Word	Noun	Adjective	Verb	Adverb
burial mound	Yes	No	No	No
grave mound	Yes	No	No	No

As nouns, burial mound and grave mound are synonyms defined as:

burial mound and grave mound: (archeology) a heap of earth placed over prehistoric tombs

Other synonyms of burial mound include barrow, tumulus.

burial mound (noun)	grave mound (noun)
(archeology) a heap of earth placed over prehistoric tombs	(archeology) a heap of earth placed over prehistoric tombs