American buffalo vs Bison bison

American buffalo and Bison bison both are nouns.

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

As nouns, American buffalo and Bison bison are synonyms defined as:

American buffalo and Bison bison: large shaggy-haired brown bison of North American plains

Other synonyms of American buffalo include American bison, buffalo.

American buffalo (noun)	Bison bison (noun)
large shaggy-haired brown bison of North American plains	large shaggy-haired brown bison of North American plains