patina

Concise Oxford English Dictionary © 2008 Oxford University Press:
patina /ˈpatɪnə/

▶noun

• 1 a green or brown film on the surface of old bronze.

• 2 a sheen on wooden furniture produced by age and polishing.

• 3 any distinctive surface appearance acquired over time.

– derivatives
patinated adjective,
patination noun.

– origin C18: from Ital., from L. patina ‘shallow dish’.