Source : Webster's Revised Unabridged Dictionary (1913)

Nitrile \Ni"trile\ (? or ?), n. [See {Nitro-}.] (Chem.)
   Any one of a series of cyanogen compounds; particularly, one
   of those cyanides of alcohol radicals which, by boiling with
   acids or alkalies, produce a carboxyl acid, with the
   elimination of the nitrogen as ammonia.

   Note: The nitriles are named with reference to the acids
         produced by their decomposition, thus, hydrocyanic acid
         is {formic nitrile}, and methyl cyanide is {acetic
         nitrile}.

Source : WordNet®

nitrile
     n : any of a class of organic compounds containing the cyano
         radical -CN [syn: {nitril}, {cyanide}]