hill vs grave mound

hill and grave mound both are nouns.

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

As nouns, grave mound is a hyponym of hill; that is, grave mound is a word with a more specific, narrower meaning than hill:

hill: structure consisting of an artificial heap or bank usually of earth or stones
grave mound: (archeology) a heap of earth placed over prehistoric tombs

Other hyponyms of hill include barbette, barrow, burial mound, tumulus, embankment, snow bank, snowbank.

hill (noun)	grave mound (noun)
(baseball) the slight elevation on which the pitcher stands	(archeology) a heap of earth placed over prehistoric tombs
structure consisting of an artificial heap or bank usually of earth or stones
a local and well-defined elevation of the land

hill (verb)	grave mound (verb)
form into a hill