Dictionary.net

Pigments causing darkness in skin, hair, feathers, etc. They are irregular polymeric structures and are divided into three groups: allomelanins in the plant kingdom and eumelanins and phaeomelanins in the animal kingdom.

The dark or black pigment in the epidermis and hair in darkskinned races, and in the chorioid coat of the eye.

Nitrogenous black pigment in epithelium, choroid, etc.

Black or dark-brown pigment, as of the retina; haemozoin.

A dark pigment from choroid, hair, and other dark tissues; also, from melanotic tumors.

The brown, amorphous pigments present normally in the skin in the hair, the retina, and the urine, and occurring pathologically in the blood. [Gr.]