The Collaborative International Dictionary of English v.0.48:

Mosque \Mosque\ (m[o^]sk), n. [F. mosqu['e]e, Sp. mezquita, Ar.
   masjid, from sajada to bend, adore.]
   A Mohammedan church or place of religious worship. [Written
   also mosk.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

mosque
    n 1: (Islam) a Muslim place of worship that usually has a
         minaret