pig ‧ ment /ˈpɪɡmənt/ BrE AmE noun [uncountable and countable]
[ Date: 1100-1200 ; Language: Latin ; Origin: pigmentum , from pingere 'to paint' ]
a natural substance that makes skin, hair, plants etc a particular colour:
Melanin is the dark brown pigment of the hair, skin and eyes.
The artist Sandy Lee uses natural pigments in her work.