What does "nitrile" mean?

Nitrile: 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.