/ ˈpætɪnə; NAmE pəˈtiːnə/ noun [ usually sing. ]
1.
a green, black or brown layer that forms on the surface of some metals
2.
a thin layer that forms on other materials; the shiny surface that develops on wood or leather when it is polished :
( figurative )
He looked relaxed and elegant and had the patina of success.
••
WORD ORIGIN
mid 18th cent.: from Italian , from Latin patina shallow dish.