"Anodized" refers to a process that adds a protective layer to a metal surface, often aluminum, to make it more durable, resistant to corrosion, or to create a specific color or texture. Full definition
The back of the phone is made of anodized aluminum with a stainless steel Apple logo. (theverge.com)
DONALD JUDD Untitled (Bernstein 90 - 01) 1990 black anodized aluminum with clear Plexiglas 10 units, each 9 x 40 x 31 inches (22.9 x 101.6 x 78.7 cm) (mnuchingallery.com)
The $ 199 August Smart Lock is made of anodized aluminum with a 3.25 - inch diameter. (cnet.com)