The Collaborative International Dictionary of English v.0.48:

Gheber \Ghe"ber\, Ghebre \Ghe"bre\, n. [Pers. ghebr: cf. F.
   Gu[`e]bre. Cf. Giaour.]
   A worshiper of fire; a Zoroastrian; a Parsee.
   [1913 Webster]