Au"rochs (&add;"r&obreve;ks), n. [G. auerochs, OHG. ūrohso; ūr (cf. AS. ūr) + ohso ox, G. ochs. Cf. Owre, Ox.] (Zoöl.) The European bison (Bison bonasus, or Europæus), once widely distributed, but now nearly extinct, except where protected in the Lithuanian forests, and perhaps in the Caucasus. It is distinct from the Urus of Cæsar, with which it has often been confused.