melanin

mel·a·nin   (měl'ə-nĭn)    n.  Any of a group of naturally occurring dark pigments, especially the pigment found in skin, hair, fur, and feathers.

melanin [(mel-uh-nin)]

A dark brown coloring found in the body, especially in the skin and hair. Produced by special skin cells that are sensitive to sunlight, melanin protects the body by absorbing ultraviolet radiation from the sun.

Note: The amount of melanin present in the skin determines the color of a person's complexion: people with a large amount have dark skin, whereas those with very little have fair skin. Melanin is also responsible for tanning.

melanin 

Main Entry: mel·a·nin
Pronunciation: 'mel-&-n&n
Function: noun
: any of various black, dark brown, reddish brown, or yellow pigments ofanimal or plant structures (as skin, hair, the choroid, or a raw potato when exposed to air); especially : any of numerous animal pigments that are essentially polymeric derivatives ofindole formed by enzymatic modification of tyrosine

melanin mel·a·nin (měl'ə-nĭn)
n.
Any of a group of naturally occurring dark pigments composed of granules of highly irregular polymers that usually contain nitrogen or sulfur atoms, especially the pigment found in skin, hair, fur, and feathers.

melanin   (měl'ə-nĭn)  Pronunciation Key  Any of various pigments that are responsible for the dark color of the skin, hair, scales, feathers, and eyes of animals and are also found in plants, fungi, and bacteria. Melanins are polymers, often bound to proteins, and in the animal kingdom are built from compounds produced by the oxidation of the amino acid tyrosine.