patina n.

"greenish encrustation on old bronze," 1748, from French patine (18c.), from Italian patina. This appears to be from Latin patina "shallow pan, dish, stew-pan" (from Greek patane "plate, dish," from PIE *pet-ano-, from root *pete- "to spread"), but it is uncertain why, as patina was found on many ancient objects other than bronze plates and pans. It was considered to add greatly to the beauty of antique bronzes, hence the sense of "refinement, cultural sophistication" recorded by 1933. Extended by the 1890s to the surface textures of other works of decorative arts.