n. The aurochs, or bonasus, a European wild ox: hence applied to several similar animals, recent and extinct.n. 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.n. [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.n. A name applied by Indian sportsmen to the gaur, Bibos (or Gavæus) gaurus, in distinction to ‘buffalo,’ which is used for Bos buffelus.