Source : Webster's Revised Unabridged Dictionary (1913)

Bison \Bi"son\ (b[imac]"s[o^]n; 277), n. [L. bison, Gr. bi`swn,
   a wild ox; akin to OHG. wisunt, wisant, G. wisent, AS.
   wesend, Icel. v[=i]sundr: cf. F. bison.] (Zo["o]l.)
   (a) The aurochs or European bison.
   (b) The American bison buffalo ({Bison Americanus}), a large,
       gregarious bovine quadruped with shaggy mane and short
       black horns, which formerly roamed in herds over most of
       the temperate portion of North America, but is now
       restricted to very limited districts in the region of the
       Rocky Mountains, and is rapidly decreasing in numbers.