Source : Webster's Revised Unabridged Dictionary (1913)

Urdu \Ur"du\, n. [Hind. urd[=u].]
   The language more generally called {Hindustanee}.

Source : WordNet®

Urdu
     adj : relating to the Urdu language; "Urdu poetry"
     n : the official literary language of Pakistan, closely related
         to Hindi; widely used in India (mostly by Moslems);
         written in Arabic script