In a broader sense, skin/mucosa pigmentation refers to the storage of pigments (pigmentum = colour, dye) in the skin, skin appendages (hair, nails), eyes and mucous membrane. In humans, the most important pigments are melanin, oxidised haemoglobin and its derivatives haemosiderin, carotenoids and bile dyes. Their composition and density define the skin colour.
In a narrower sense, pigmentation is understood to be melanotic pigmentation (see also Pigment), i.e. the incorporation of the " melanocyte product" melanin into human cells.