lightyoudaoicibaDictYouDict[light 词源字典]
light: [OE] English has two distinct words light. The one meaning ‘illumination’ comes ultimately from Indo-European *leuk-, *louk-, *luk-, which also produced Greek leukós ‘white’ (source of English leukaemia [20]) and Latin lūx ‘light’ (from which English gets lucifer [OE], literally ‘light-bearer’), lūmen ‘light’ (whence English luminous [15]), lūcēre ‘shine’ (source of English lucid [16]), lūstrāre ‘light up’ (whence English illustrate and lustre [16]), and lūna ‘moon’ (source of English lunar).

Its main prehistoric West Germanic derivative was *leukhtam, from which come German and Dutch licht and English light. The word lynx may be related. Light ‘not heavy’ comes from a prehistoric Germanic *lingkhtaz, a close relative of which produced English lung (the word lung thus etymologically denotes ‘something full of air and not heavy’, and indeed lungs were, and animal lungs still are called lights in English).

=> illustrate, leukaemia, lucid, luminous, lunar, lustre, lynx; lung[light etymology, light origin, 英语词源]
alight (adj.)youdaoicibaDictYouDict
"on fire," early 15c., apparently from Middle English aliht, past participle of alihton (Old English on-lihtan) "to light up," also "to shine upon" (see light (n.)).
eclair (n.)youdaoicibaDictYouDict
"small, oblong cake filled with cream or custard and glazed or iced," 1861, from French éclair, literally "lightning," from Old French esclair "light, daylight, flash of light," verbal noun from esclairare "to light up, illuminate, make shine" (12c.), formerly esclairer, ultimately from Latin exclarare "light up, illumine," from ex- "out" (see ex-) + clarus "clear" (see clear (adj.)).
enlighten (v.)youdaoicibaDictYouDict
late 14c., "to remove the dimness or blindness" (usually figurative, from one's eyes or heart); see en- (1) + lighten. From 1660s as "supply with intellectual light." Literal senses are later and less common in English: "put light in" is from 1580s; "shed light upon" is from 1610s. Related: Enlightened; enlightening. Old English had inlihtan "to illuminate, enlighten."
famous (adj.)youdaoicibaDictYouDict
late 14c., "celebrated in public report, renowned, well-known" also "notorious, infamous," from Anglo-French famous, Old French fameus (Modern French fameux), from Latin famosus "much talked of, renowned," often "infamous, notorious, of ill repute," from fama (see fame (n.)). A native word for this was Old English namcuð, literally "name-known." Catch phrase famous last words in the humorous sense "remark likely to prove fatally wrong" is attested from 1921 (early lists of them include "Let's see if it's loaded ... We'll get across before the train comes ... Which one is the third rail? ... Light up, it can't explode").
hit (v.)youdaoicibaDictYouDict
late Old English hyttan, hittan "come upon, meet with, fall in with, 'hit' upon," from a Scandinavian source such as Old Norse hitta "to light upon, meet with," also "to hit, strike;" Swedish hitta "to find," Danish and Norwegian hitte "to hit, find," from Proto-Germanic *hitjan, of uncertain origin. Related: Hitting. Meaning shifted in late Old English period to "strike," via "to reach with a blow or missile," and replaced Old English slean in this sense. Original sense survives in phrases such as hit it off (1780, earlier in same sense hit it, 1630s) and is revived in hit on (1970s).

Underworld slang meaning "to kill by plan" is 1955 (as a noun in this sense from 1970). To hit the bottle "drink alcohol" is from 1889. To hit the nail on the head (1570s) is from archery. Hit the road "leave" is from 1873; to hit (someone) up "request something" is from 1917. Hit and run is 1899 as a baseball play, 1924 as a driver failing to stop at a crash he caused. To not know what hit (one) is from 1923.
illuminate (v.)youdaoicibaDictYouDict
c. 1500, "to light up, shine on," a back-formation from illumination, or else from Latin illuminatus, past participle of illuminare (see illumination). Earlier was enlumyen (late 14c.) "decorate written material with gold, silver, bright colors," from Old French enluminer, from Late Latin inluminare; also illumine (late 14c.). Related: Illuminated; illuminating.
illumination (n.)youdaoicibaDictYouDict
late 14c., "spiritual enlightenment," from Latin illuminationem (nominative illuminatio), from past participle stem of illuminare "to throw into light, make bright, light up;" figuratively "to set off, illustrate," from assimilated form of in- "in, into" (see in- (2)) + lumen (genitive luminis) "light," related to lucere "to shine" (see light (n.)). Meaning "action of lighting" is from 1560s.
illumine (v.)youdaoicibaDictYouDict
late 14c., "to enlighten spiritually;" mid-15c., "to light up, shine light on," from Old French illuminer, from Latin illuminare (see illumination). Related: illumined.
illustrate (v.)youdaoicibaDictYouDict
1520s, "light up, shed light on;" 1610s, "educate by means of examples," back-formation from illustration, and in some cases from Latin illustratus, past participle of illustrare (see illustration). Sense of "provide pictures to explain or decorate" is 1630s. Related: Illustrated; illustrating.
illustration (n.)youdaoicibaDictYouDict
c. 1400, "a shining;" early 15c., "a manifestation;" mid-15c., "a spiritual illumination," from Old French illustration "apparition, appearance," and directly from Latin illustrationem (nominative illustratio) "vivid representation" (in writing), literally "an enlightening," from past participle stem of illustrare "light up, make light, illuminate;" figuratively "make clear, disclose, explain; adorn, render distinguished," from assimilated form of in- "in" (see in- (2)) + lustrare "make bright, illuminate," related to lucere "shine," lux "light" (see light (n.)). Mental sense of "act of making clear in the mind" is from 1580s. Meaning "an illustrative picture" is from 1816.
irradiate (v.)youdaoicibaDictYouDict
c. 1600, "to cast beams of light upon," from Latin irradiatus, past participle of irradiare "shine forth," from assimilated form of in- "into, in" (see in- (2)) + radiare "to shine" (see radiate). Meaning "expose to radiation other than light" (originally X-rays) is from 1901. Related: Irradiated; irradiating.
lighten (v.2)youdaoicibaDictYouDict
"shed light upon, illuminate, brighten," early 14c., from light (n.) -en (1). Meaning "to grow brighter" is late 14c. Of faces, expressions, etc., from 1795. Related: Lightened; lightening.
limn (v.)youdaoicibaDictYouDict
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.
tilt (v.2)youdaoicibaDictYouDict
"to joust," 1590s, from tilt (n.1). Related: Tilted; tilting. The figurative sense of tilting at windmills is suggested in English by 1798; the image is from Don Quixote, who mistook them for giants.
So saying, and heartily recommending himself to his lady Dulcinea, whom he implored to succour him in this emergency, bracing on his target, and setting his lance in the rest, he put his Rozinante to full speed, and assaulting the nearest windmill, thrust it into one of the sails, which was drove about by the wind with so much fury, that the lance was shivered to pieces, and both knight and steed whirled aloft, and overthrown in very bad plight upon the plain. [Smollett translation, 1755]