Ver·di·gris n.
 1. Chem. A green poisonous substance used as a pigment and drug, obtained by the action of acetic acid on copper, and consisting essentially of a complex mixture of several basic copper acetates.
 2. The green rust formed on copper.  [Colloq.]
 Note: ☞ This rust is a carbonate of copper, and should not be confounded with true verdigris.
 Blue verdigris Chem., a verdigris having a blue color, used as 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.