melanin

noun

mel·​a·​nin ˈme-lə-nən 

plural melanins

: any of various black, brown, reddish-brown, reddish-yellow, or yellow pigments of living organisms that in animals are typically produced in melanocytes by the oxidation of tyrosine followed by polymerization and are found especially in skin, hair, feathers, and eyes

Scientists know that all melanin molecules consist of long chains made mostly of derivatives of the amino acid tyrosine, but the individual units of the chain connect in random order.

—Corinna Wu

Melanin performs an array of functions for modern organisms, such as camouflage, photo protection, and display.

—Margaret Jones

especially : eumelanin

Tyrosinase enzymes are needed for the manufacture of melanin, the dark pigment that forms the color base of feathers.

—Philip C. Whitford

Brown spots and birthmarks contain especially high concentrations of melanin, the substance that gives skin its color.

—USA Today

see also neuromelanin, pheomelanin

Examples of melanin in a Sentence

Recent Examples on the Web

Essentially, hydroquinone decreases the production of melanin by inhibiting a pigment-producing enzyme called tyrosinase. —Taryn Brooke, Allure, 13 Nov. 2023

In addition to the amount of melanin produced, the type matters, too. —Daryl Austin, USA TODAY, 1 Sep. 2023

There’s also the sun-exposure factor: Ultraviolet rays trigger the production of melanin as a protective mechanism.4 In short, that means that the sun plays a part in any and all types of hyperpigmentation. —Melanie Rud, SELF, 29 Aug. 2023

If products are just being evaluated in this very one-dimensional way, biases will go undetected and unmitigated Alice Xiang, global head of AI Ethics at Sony A person’s skin color comes from the interplay of light with proteins, blood cells, and pigments such as melanin. —Paresh Dave, WIRED, 3 Oct. 2023

Yara Shahidi brought melanin to Peter Pan, Black Girl Magic to Grown-Ish, and most recently, a sprinkle of fame to study time. —Essence, 30 Sep. 2023

These cells develop in embryos in the same way those in humans do, use the same genetic programs and make the same melanins. —Craig Ceol, The Conversation, 10 July 2023

Tanning serves as the body’s protective response to skin damage from ultraviolet rays, stimulating melanocytes to produce melanin. —Enrique Torchia, Fortune Well, 20 Aug. 2023

So what's going on with this curious ruminant? Thane Maynard, director of the Cincinnati Zoo and Botanical Garden, said the deer was born with partial albinism, a condition that limits the production of melanin, the pigment that colors skin, eyes and fur. —The Enquirer, 18 Aug. 2023

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Word History

Etymology

Greek melan-, stem of mélās "black, dark" + -in entry 1, after Italian melaina — more at melano-

Note: The term melaina was introduced in a study of squid ink by the Italian chemist Bartolomeo Bizio (1791-1862), "Ricerche chimiche sovra l'inchiostro della Seppia," Giornale di fisica, chimica, storia naturale, medicina ed arte, decade 2, tomo 8 (1825), p. 105. Bizio formed the word from Greek mélās "black" and aeí "always" because the substance he had isolated retained its color no matter what acid or other potent chemical it was exposed to ("Questo principio animal particolarissimo il fu chiamato così dal greco mélas, nero, ed aeì sempre, che vale materia sempre nera, conciossachè gli acidi, il cloro, e tutto che vi è di più potente, non bastano a mutarlo di colore.")

First Known Use

1843, in the meaning defined above

Kids Definition

melanin

noun

mel·​a·​nin ˈmel-ə-nən 

: a dark brown or black animal or plant pigment that in human beings makes some skins darker than others

Etymology

derived from Greek melan-, melas "black" — related to melancholy

Medical Definition

melanin

noun

mel·​a·​nin ˈmel-ə-nən 

: any of various black, brown, reddish-brown, reddish-yellow, or yellow pigments of living organisms that in animals are typically produced in melanocytes by the oxidation of tyrosine followed by polymerization and are found especially in skin, hair, feathers, and eyes

Scientists know that all melanin molecules consist of long chains made mostly of derivatives of the amino acid tyrosine, but the individual units of the chain connect in random order.

—Corinna Wu, Science News

especially : eumelanin

Brown spots and birthmarks contain especially high concentrations of melanin, the substance that gives skin its color.

—USA Today

Natural melanin surrounds and protects our cells not only by absorbing ultraviolet radiation, but also by scattering it and making it lose energy, rendering it harmless.

—Rowann Gilman, Prevention

see also neuromelanin, pheomelanin