early 15c., "to illuminate" (manuscripts), altered from Middle English luminen, "to illuminate manuscripts" (late 14c.), from Old French luminer "light up, illuminate," from Latin luminare "illuminate, burnish," from lumen (genitive luminis) "radiant energy, light," related to lucere "to shine" (see light, n.). Sense of "portray, depict" first recorded 1590s. Related: Limned.