Source : Webster's Revised Unabridged Dictionary (1913)

Urus \U"rus\, n. [L.; of Teutonic origin. See {Aurochs}.]
   (Zo["o]l.)
   A very large, powerful, and savage extinct bovine animal
   ({Bos urus or primigenius}) anciently abundant in Europe. It
   appears to have still existed in the time of Julius C[ae]sar.
   It had very large horns, and was hardly capable of
   domestication. Called also, {ur}, {ure}, and {tur}.

Source : WordNet®

urus
     n : large recently extinct long-horned European wild ox;
         considered one of the ancestors of domestic cattle [syn:
         {aurochs}, {Bos primigenius}]