late 14c., "a red dye," from Latin pigmentum "coloring matter, pigment, paint," figuratively "ornament," from stem of pingere "to color, paint" (see paint (v.)). By 1610s in the broader sense "any substance that is or can be used by painters to impart color" (technically a dry substance that can be powdered and mixed with a liquid medium).
Variants of this word could have been known in Old English and Middle English (compare 12c. pyhmentum, laterpiment) with a sense of "a spiced drink, a remedy or concoction containing spices," based on a secondary sense of the Latin word in Medieval Latin. As a verb from 1900. Related: Pigmented. Also pigmental"of or pertaining to pigment" (1836); pigmentary (1835).