Brown hair, also referred to as brunette (when female) or brunet (when male), is the second-most common human hair color, after black hair. It varies from light brown to dark hair. It is characterized by higher levels of the dark pigment eumelanin and lower levels of the pale pigment pheomelanin. The term brunette is the feminine form of the French word brunet, which is a diminutive form of brun meaning "brown/brown-haired", the feminine of which is brune.

Source: Wikipedia