graveyard vs burial site

graveyard and burial site both are nouns.

Word	Noun	Adjective	Verb	Adverb
graveyard	Yes	No	No	No
burial site	Yes	No	No	No

As nouns, graveyard and burial site are synonyms defined as:

Other synonyms of graveyard include burial ground, burying ground, cemetery, memorial park, necropolis.

graveyard (noun)	burial site (noun)
a tract of land used for burials	a tract of land used for burials