a. [ From Prussia, the country: cf. F. prussien. ] Of or pertaining to Prussia. -- n. A native or inhabitant of Prussia. [ 1913 Webster ]

Prussian blue (Chem.), any one of several complex double cyanides of ferrous and ferric iron; specifically, a dark blue amorphous substance having a coppery luster, obtained by adding a solution of potassium ferrocyanide (yellow prussiate of potash) to a ferric salt. It is used in dyeing, in ink, etc. Called also Williamson's blue, insoluble Prussian blue, Berlin blue, etc. --
Prussian carp (Zool.) See Gibel. --
Prussian green. (Chem.) Same as Berlin green, under Berlin. [ 1913 Webster ]

n. [ Cf. F. prussiate. ] (Chem.) A salt of prussic acid; a cyanide. [ 1913 Webster ]

Red prussiate of potash. See Potassium ferricyanide, under Ferricyanide. --
Yellow prussiate of potash. See Potassium ferrocyanide, under Ferrocyanide. [ 1913 Webster ]

a. [ Cf. F. prussique. ] (Old Chem.) designating the acid now called hydrocyanic acid, but formerly called prussic acid, because Prussian blue is derived from it or its compounds. See Hydrocyanic. [ 1913 Webster ]