What does "verdigris" mean?

Verdigris: The green rust formed on copper. [Colloq.] Note: This rust is a carbonate of copper, and should not be confounded with true verdigris. U. S. Disp. Blue verdigris (Chem.), a verdigris having a blue color, used a pigment, etc. -- Distilled verdigris (Old Chem.), an acid copper acetate; -- so called because the acetic acid used in making it was obtained from distilled vinegar. -- Verdigris green, clear bluish green, the color of verdigris.