Source : Webster's Revised Unabridged Dictionary (1913)

Aurochs \Au"rochs\ ([add]"r[o^]ks), n. [G. auerochs, OHG.
   [=u]rohso; [=u]r (cf. AS. [=u]r) + ohso ox, G. ochs. Cf.
   {Owre}, {Ox}.] (Zo["o]l.)
   The European bison ({Bison bonasus, or Europ[ae]us}), 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 C[ae]sar, with
   which it has often been confused.