The Collaborative International Dictionary of English v.0.48:
Urdu \Ur"du\, n. [Hind. urd[=u].] The language more generally called Hindustanee. [1913 Webster]WordNet (r) 3.0 (2006):
Urdu n 1: the official literary language of Pakistan, closely related to Hindi; widely used in India (mostly by Moslems); written in Arabic script