Brown hair is the second most common hair color, with black being the other most common.

200px|thumb|right|Actress Evangeline Lilly with brown hair Brown hair (also referred to as chestnut and cinnamon) varies from light brown to almost black hair. It is characterized by higher levels of the dark pigment eumelanin and lower levels of the pale pigment phaeomelanin. Its strands are thicker than those of fair hair but not as much as those of red hair. People with brown hair are often referred to as brunettes, the feminine form, and brunets, the masculine term. Brown hair is common among West Eurasians-- especially in central and southern Europe, West Asia, and North Africa, where it transitions smoothly into blackish-brown and pure black hair.

Etymology and grammar

The term brunette is the feminine of French brunet, which is a diminutive of brun or brune, meaning brown, from Latin brunus (brown), ultimately of Germanic origin (cf. English 'brown', German 'braun'). Brunette literally means “little brown-haired girl", but in English usage it has largely lost the diminutive meaning, and simply refers to any dark-haired girl or woman. Although brunet is the reference to a boy or man with dark hair; it can also be used to refer to either sex.

Some people use the word brunet(te) to simply refer to people having brown hair. Men or women with lighter shades of brown hair may actually be referred to as "light brunet(te)s". The usual term brunet(te) describes a person with medium to dark brown hair.Fact: date=August 2008

Biochemistry

The pigment Eumelanin (literally meaning “good” melanin) gives brown hair its distinctive color. Brown hair has more eumelanin than blond hair but also has much less than black. There are two different types of eumelanin, which are distinguished from each other by their pattern of polymer bonds. The two types are black eumelanin and brown eumelanin. Black eumelanin is the darkest, brown eumelanin is lighter than black. Black eumelanin is mostly present in non-Europeans and aged Europeans, while brown eumelanin is mostly present in young Europeans, and people of other ethnicities. A small amount of black eumelanin in the absence of other pigments causes grey hair. A small amount of brown eumelanin in the absence of other pigments causes yellow (blond) color hair. Brown-haired people have medium-thick strands of hair.

Brown haired people are thought to produce more skin-protecting eumelanin and are associated with having a more even skin tone. The range of skin colors associated with brown hair is vast, ranging from the palest of skin tone to an olive complexion. Brunettes can have dark or light eyes. Occasionally, natural blonde or red hair will darken over time, resulting in a brown-haired individual with light colored eyes.

Varieties of brunette-brunet