Pronunciation: (bī'sun, -zun), [key]
1. Also called American bison, American buffalo. a North American, oxlike ruminant, Bison bison, having a large head and high, humped shoulders: formerly common in North America, its small remaining population in isolated western areas of the U.S. and Canada is now protected.
2. Also called wisent. a related animal, Bison bonasus, of Europe, less shaggy and slightly larger than the American bison: now greatly reduced in number.Cf. buffalo.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.