melanin
Meaning of melanin: Melanin is the pigment responsible for skin, hair, and eye color that also helps absorb and limit damage from ultraviolet light.
Definition of melanin
Melanin is a natural pigment produced by specialized cells called melanocytes, found mainly in the skin, hair follicles, and the eye. It is responsible for the range of natural color seen in skin, hair, and the iris, with darker coloring generally reflecting a greater amount of melanin produced.
Beyond its role in coloring, melanin absorbs ultraviolet radiation from sunlight, helping to reduce the amount of this energy that reaches deeper skin layers and limiting the damage ultraviolet exposure can cause to skin cells over time. Melanin production typically increases with sun exposure, which is part of what produces a tan.
Changes in melanin production underlie several skin conditions, including areas of unusually light or dark skin, and melanin producing cells are also the origin of melanoma, a type of skin cancer that arises when these cells grow and divide abnormally.
Used in a sentence
The dermatologic examination noted an area of increased melanin in the skin lesion.
Good to know
Melanin production increases with ultraviolet exposure, which provides some added protection over time, but this response does not eliminate the skin damage that ultraviolet exposure can still cause.
Word origin
Where “melanin” comes from
Formed from Greek melas, melanos, meaning black, and the chemical suffix -in.