Source : Webster's Revised Unabridged Dictionary (1913)

Nitric \Ni"tric\, a. [Cf. F. nitrique. See {Niter}.] (Chem.)
   Of, pertaining to, or containing, nitrogen; specifically,
   designating any one of those compounds in which, as
   contrasted with nitrous compounds, the element has a higher
   valence; as, nitric oxide; nitric acid.

   {Nitric acid}, a colorless or yellowish liquid obtained by
      distilling a nitrate with sulphuric acid. It is powerfully
      corrosive, being a strong acid, and in decomposition a
      strong oxidizer.

   {Nitric anhydride}, a white crystalline oxide of nitrogen
      ({N2O5}), called {nitric pentoxide}, and regarded as the
      anhydride of nitric acid.

   {Nitric oxide}, a colorless poisous gas ({NO}) obtained by
      treating nitric acid with copper. On contact with the air
      or with oxygen, it becomes reddish brown from the
      formation of nitric dioxide or peroxide.

Source : WordNet®

nitric oxide
     n : a poisonous red-brown gas (NO)