lac (n.) Look up lac at
"red resinous substance," 1550s (perhaps via Middle French lacce), earlier lacca (early 15c., from Medieval Latin form lacca), from Persian lak, from Hindi lakh (Prakrit lakkha), from Sanskrit laksha "red dye," of uncertain origin. According to Klein, literally "one hundred thousand," in reference to the insects that gather in great numbers on the trees and make the resin run out. But others say lakh is an alteration of Sanskrit rakh, from an IE root word for "color, dye" [Watkins]. Still another guess is that Sanskrit laksha is related to English lax, lox "salmon," and the substance was perhaps originally so called from being somewhat the color of salmon [Barnhart].