Source : Webster's Revised Unabridged Dictionary (1913)

Nitrite \Ni"trite\, n. [Cf. F. nitrite. See {Niter}.] (Chem.)
   A salt of nitrous acid.

   {Amyl nitrite}, a yellow oily volatile liquid, used in
      medicine as a depressant and a vaso-dilator. Its
      inhalation produces an instantaneous flushing of the face.

Source : WordNet®

nitrite
     n : the radical -NO2 or any compound containing it (such as a
         salt or ester of nitrous acid)