"gloss, radiance, quality of shining by reflecting light," 1520s, from French lustre "gloss, radiance" (14c.), common Romanic (cognates: Spanish and Portuguese lustre, Rumanian lustru, Italian lustro "splendor, brilliancy"), a noun ultimately from Latin lustrare "spread light over, brighten, illumine," which is related to lustrum "purification" (from PIE *leuk-stro-, suffixed form of root *leuk- "light, brightness").
Especially "quality of glossiness or radiance in a textile material or fabric." Figurative meaning "radiant beauty" is from c. 1600; that of "splendor, renown" is from 1550s. Lusterware, also lustre-ware, "stoneware or crockery having surface ornamentations in metallic colors," is attested by 1820.
Proto-Indo-European root meaning "light, brightness."
It forms all or part of: allumette; elucidate; illumination; illustration; lea; leukemia; leuko-; light (n.) "brightness, radiant energy;" lightning; limn; link (n.2) "torch of pitch, tow, etc.;" lucent; lucid; Lucifer; luciferase; luciferous; lucifugous; lucubrate; lucubration; luculent; lumen; Luminal; luminary; luminate; luminescence; luminous; luna; lunacy; lunar; Lunarian; lunate; lunation; lunatic; lune; lunette; luni-; luster; lustrum; lux; pellucid; sublunary; translucent.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit rocate "shines;" Armenian lois "light," lusin "moon;" Greek leukos "bright, shining, white;" Latin lucere "to shine," lux "light," lucidus "clear;" Old Church Slavonic luci "light;" Lithuanian laukas "pale;" Welsh llug "gleam, glimmer;" Old Irish loche "lightning," luchair "brightness;" Hittite lukezi "is bright;" Old English leht, leoht "light, daylight; spiritual illumination," German Licht, Gothic liuhaþ "light."
measure of quality of a diamond, c. 1600, from water (n.1), perhaps as a translation of Arabic ma' "water," which also is used in the sense "luster, splendor."
