ALL meanings of blue copperas
blue cop·per·as
B b - noun blue copperas a salt, copper sulfate, CuSO 4 ⋅5H 2 O, occurring naturally as large transparent, deep-blue triclinic crystals, appearing in its anhydrous state as a white powder: used chiefly as a mordant, insecticide, fungicide, and in engraving. 1