/ˈmɛlənɪn/
[noun] A natural pigment found in the skin, hair, and eyes of humans and animals that gives them their colour and helps protect the skin from the sun's harmful rays.
The word 'melanin' comes from the Greek word for 'black' — the same root that gave us 'melancholy', meaning a darkness of the mind.
The story of melanin begins in ancient Greece, with the word 'melas' (μέλας), meaning 'black' or 'dark'. This was one of the most versatile colour words in the Greek language, used to describe everything from dark wine to the depths of the sea. Greek writers used it poetically and practically alike, and it embedded itself deeply into the vocabulary of natural description. It is one of those foundational roots that quietly spread through the centuries into an enormous number of scientific and everyday words.
The word entered the world of science in the 19th century, when European chemists and biologists began systematically naming the pigments and substances they were studying. In 1839, the Swedish chemist Jöns Jacob Berzelius — famous for establishing the modern chemical symbol system — coined the term 'melanin' by taking the Greek root 'melas' and adding the Latin-style suffix '-in', commonly used at the time to name chemical substances (as in 'keratin', 'albumin', and 'gelatin'). Berzelius used it to describe the dark pigment found in the choroid layer of the eye, but the name quickly expanded to cover the whole family of dark biological pigments found across the natural world.
Scientifically speaking, melanin is not a single substance but a group of related pigments produced by specialised cells called melanocytes. These cells exist in the skin, hair follicles, and eyes, and they produce melanin through a chemical process involving an amino acid called tyrosine. The amount and type of melanin a person has — two main types are eumelanin, which is brown-black, and pheomelanin, which is red-yellow — largely determines the colour of their skin and hair. Higher melanin concentrations provide greater protection against ultraviolet radiation, which is why the body produces more melanin when exposed to sunlight, resulting in a tan.
The Greek root 'melas' has had a remarkably productive life in English, branching into many directions. One of its most famous descendants is 'melancholy', which came into English via Latin 'melancholia' and Old French 'melancolie'. The ancient Greeks believed that moods were controlled by four bodily fluids called 'humours', and that an excess of black bile — in Greek, 'melan khole' (μέλαν χολή), meaning 'black bile' — caused a state of deep sadness and gloom. So the same root that names our skin pigment also names a mood of deep sadness: Greek 'melas' → Latin 'melancholia' → Old French 'melancolie' → Middle English 'melancholy'.
The root 'melas' also gave rise to 'melanoma', the dangerous form of skin cancer that develops in melanocytes — formed from Greek 'melas' + Greek '-oma' (meaning tumour) → directly into modern medical Latin and then English 'melanoma'. Elsewhere, 'Melanesia', the name for the Pacific island group, comes from Greek 'melas' + Greek 'nesos' (island), coined in the 19th century to describe the darker complexions of the region's inhabitants — a naming choice that reflects the racial assumptions of its time. Even 'marmalade' has a distant cousin connection, though more disputed. What is clear is that 'melas' is one of antiquity's most persistent roots, colouring — quite literally — the language of science, medicine, and emotion across more than two thousand years.