Definition of calcium cyanide
: a compound Ca(CN)2 that gives off hydrogen cyanide on exposure to air, is made usually in impure black or gray flakes, powder, or cast blocks by heating crude calcium cyanamide in the presence of salt in an electric furnace, and is used chiefly as an insecticide and rodenticide and in making hydrogen cyanide and ferrocyanides — called also
black cyanide
