Source : Webster's Revised Unabridged Dictionary (1913)

Nitrohydrochloric \Ni`tro*hy`dro*chlo"ric\, a. [Nitro- +
   hydrochloric.] (Chem.)
   Of, pertaining to, or containing, nitric and hydrochloric
   acids.

   {Nitrohydrochloric acid}, a mixture of nitric and
      hydrochloric acids, usually in the proportion of one part
      of the former to three of the latter, and remarkable for
      its solvent action on gold and platinum; -- called also
      {nitromuriatic acid}, and {aqua regia}.

Source : WordNet®

nitrohydrochloric acid
     n : a yellow fuming corrosive mixture of nitric and hydrochloric
         acid that dissolves metals (including gold) [syn: {aqua
         regia}]