The Collaborative International Dictionary of English v.0.48:

Cyanic \Cy*an"ic\ (s?-?n"?k), a. [Gr. ky`anos a dark blue
   substance: cf. F. cyanique. Cf. Kyanite.]
   1. Pertaining to, or containing, cyanogen.
      [1913 Webster]

   2. Of or pertaining to a blue color.
      [1913 Webster]

   Cyanic acid (Chem.), an acid, HOCN, derived from
      cyanogen, well known in its salts, but never isolated in
      the free state.

   Cyanic colors (Bot.), those colors (of flowers) having some
      tinge of blue; -- opposed to xanthic colors. A color of
      either series may pass into red or white, but not into the
      opposing color. Red and pure white are more common among
      flowers of cyanic tendency than in those of the other
      class.
      [1913 Webster]

WordNet (r) 3.0 (2006):

cyanic acid
    n 1: a colorless poisonous volatile liquid acid that hydrolyzes
         readily to ammonia and carbon dioxide