Pigmentation (noun)

1. The coloring of the skin, hair, or eyes, especially due to the presence of melanin and other pigments in the skin.
2. The process by which skin, hair, or eyes acquire color, due to the presence of melanin and other pigments in the skin.

Origin:

From late latin pigmentum 'paint' + -ation.

Examples:

1. The pigmentation of his skin was darkened by the sun, giving him a tan.
2. The pigmentation in her hair was due to the presence of melanin, which provides color and protection from the sun.
3. The pigmentation in his eyes was due to the presence of melanin, which determines the color of the iris.
4. The pigmentation in her skin was lighter than her siblings, due to a different genetic makeup.
5. The pigmentation in the butterfly's wings was due to the presence of pigments that reflect light and produce iridescent colors.