bison

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A bovine mammal (Bison bison) of western North America, having large forequarters, a shaggy mane, and a massive head with short curved horns; a buffalo.
• noun A bovine mammal (Bison bonasus) of Europe, similar to the North American bison but with a somewhat smaller head and longer horns; a wisent.
• noun The flesh of the North American bison, used as food.

from The Century Dictionary.

• noun A name applied by Indian sportsmen to the gaur, Bibos (or Gavæus) gaurus, in distinction to ‘buffalo,’ which is used for Bos buffelus.
• noun The aurochs, or bonasus, a European wild ox: hence applied to several similar animals, recent and extinct.
• noun Bison or Bos americanus, improperly called the buffalo, an animal which formerly ranged over most of the United States and much of British America in countless numbers, now reduced to probably a few thousands, and apparently soon to become extinct as a wild animal.
• noun [capitalized] [NL.] A genus or subgenus of the family Bovidæ, including the aurochs, B. bonasus (see cut under aurochs), the American bison, B. americanus, and several related fossil species, as B. latifrons.

from the GNU version of the Collaborative International Dictionary of English.

• noun The aurochs or European bison.
• noun 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 by 1900 was restricted to very limited districts in the region of the Rocky Mountains, and was almost hunted to extinction.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A wild ox, Bison bonasus.
• noun A similar American animal, Bison bison else Bos americanus or Bisonte americano; also called a buffalo.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any of several large humped bovids having shaggy manes and large heads and short horns