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

Premature gray or white hair: Certain stem cells in our hair follicles contain melanin that provide pigment to our hair — but many people lose these stem cells with age. —Trisha Pasricha, Washington Post, 22 July 2024

The researchers found that the grapeseed product significantly reduced skin redness, skin melanin (pigment), oil production, and the size of pores. —Laura Schober, Health, 30 Sep. 2024

In that case, your body might overreact and pump out lots of (and sometimes too much) protective melanin. —Jenna Ryu, SELF, 18 Oct. 2024

Excessive melanin causes hyperpigmentation in aged skin. —New Atlas, 6 Sep. 2024

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 usually dark brown or black pigment that gives color to skin, hair, feathers, and eyes

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