Английский Этимологический словарь - light (n.)

- O.E. leht, earlier leoht. The -gh- was an Anglo-Fr. scribal attempt to render the O.E. hard -h- sound, which has since disappeared. The verb is from O.E. lyhtan, from W.Gmc. *leukhtam (also source of O.E. leoht), from PIE *leuk- "light, brightness." Meaning "something used for igniting" is from 1684. Lighthouse is from 1622.