bison vs buffalo

bison and buffalo both are nouns.

Word	Noun	Adjective	Verb	Adverb
bison	Yes	No	No	No
buffalo	Yes	No	Yes	No

As nouns, buffalo is a hyponym of bison; that is, buffalo is a word with a more specific, narrower meaning than bison:

bison: any of several large humped bovids having shaggy manes and large heads and short horns
buffalo: large shaggy-haired brown bison of North American plains

Other hyponyms of bison include American bison, American buffalo, Bison bison, aurochs, Bison bonasus, wisent.

bison (noun)	buffalo (noun)
any of several large humped bovids having shaggy manes and large heads and short horns	any of several Old World animals resembling oxen including, e.g., water buffalo, Cape buffalo
	large shaggy-haired brown bison of North American plains
	meat from an American bison

bison (verb)	buffalo (verb)
	intimidate or overawe