Source : Webster's Revised Unabridged Dictionary (1913)

Giaour \Giaour\, n. [Turk. giaur an infidel, Per. gawr, another
   form of ghebr fire worshiper. Cf. {Kaffir}, {Gheber} .]
   An infidel; -- a term applied by Turks to disbelievers in the
   Mohammedan religion, especially Christrians. --Byron.