what is verdigris
Definition of verdigris. 1  1a : a green or greenish-blue poisonous pigment resulting from the action of acetic acid on copper and consisting of one or more basic copper acetatesb : normal copper acetate Cu(C2H3O2)2Â·H2O. 2  2 : a green or bluish deposit especially of copper carbonates formed on copper, brass, or bronze surfaces.