Webster’s Revised Unabridged Dictionary · 1913
Ferrocyanic
Fer′ro·cy·an′ic (·sī·ăn′ĭk), a. [Ferro- + cyanic: cf. F. ferrocyanique.] (Chem.) Pertaining to, derived from, or designating, a ferrocyanide.
ferrocyanic acid (Chem.), a white crystalline substance, H4(CN)6Fe, of strong acid properties, obtained from potassium ferrocyanide, and regarded as the type of the ferrocyanides; — called also hydro-ferrocyanic acid, hydrogen ferrocyanide. etc.