The Collaborative International Dictionary of English v.0.48:

Jin \Jin\, Jinn \Jinn\, n.
   See Jinnee. "Solomon is said to have had power over the
   jin." --Balfour (Cyc. of India).
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Jinnee \Jin"nee\, Jinni \Jin"ni\(j[i^]n"n[=e]), n.; pl. Jinn
   (j[i^]n). [Ar.] (Arabian & Mohammedan Myth.)
   A genius or demon; one of the fabled genii, good and evil
   spirits, supposed to be the children of fire, and to have the
   power of assuming various forms. [Written also djinnee,
   genie, etc.]

   Syn: jinn; jin; djinn.
        [1913 Webster]

   Note: Jinn is also used as sing., with pl. jinns.
         [1913 Webster]