The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

   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 nitrogen dioxide (NO2, also called nitric
      dioxide or nitric peroxide).
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Nitrite \Ni"trite\, n. [Cf. F. nitrite. See Niter.] (Chem.)
   A salt or ester of nitrous acid; a compound bearing the
   -NO2 radical.
   [1913 Webster +PJC]

   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.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

nitro- \ni"tro-\pref.
   1. A combining form or an adjective denoting the presence of
      niter.
      [1913 Webster]

   2. (Chem.) A combining form (used also adjectively)
      designating certain compounds of nitrogen or of its acids;
      as nitrohydrochloric, nitrocalcite; also, designating the
      group or radical NO2, or its compounds, as nitrobenzene
      (C6H5.NO2).
      [1913 Webster]

   Nitro group, the radical NO2; -- called also nitroxyl.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Nitroxyl \Ni*trox"yl\, n. [Nitro- + oxygen + -yl.] (Chem.)
   The group -NO2, usually called the nitro group.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Chromophore \Chro"mo*phore\, n. [Gr. ? color + fe`rein to bear.]
   (Chem.)
   Any chemical group or residue (as NO2; N2; or O2) which
   imparts some decided color to the compound of which it is an
   ingredient.
   [1913 Webster]