Source : Webster's Revised Unabridged Dictionary (1913)

Ferrocyanide \Fer`ro*cy"a*nide\ (? or ?; 104), n. [Ferro- +
   cyanide.] (Chem.)
   One of a series of complex double cyanides of ferrous iron
   and some other base.

   {Potassium ferrocyanide} (Chem.), yellow prussiate of potash;
      a tough, yellow, crystalline salt, {K4(CN)6Fe}, the
      starting point in the manufacture of almost all cyanogen
      compounds, and the basis of the ferric ferrocyanate,
      prussian blue. It is obtained by strongly heating together
      potash, scrap iron, and animal matter containing nitrogen,
      as horn, leather, blood, etc., in iron pots.

Source : WordNet®

potassium ferrocyanide
     n : a cyanide comound that is prepared by the reaction of
         potassium cyanide with ferrous salts; commonly used by
         gardeners [syn: {yellow prussiate of potash}]