light (n.)

"brightness, radiant energy, that which makes things visible," Old English leht (Anglian), leoht (West Saxon), "light, daylight; spiritual illumination," from Proto-Germanic *leukhtam (source also of Old Saxon lioht, Old Frisian liacht, Middle Dutch lucht, Dutch licht, Old High German lioht, German Licht, Gothic liuhaþ "light"), from PIE root *leuk- "light, brightness."

The -gh- was an Anglo-French scribal attempt to render the Germanic hard -h- sound, which has since disappeared from this word. The figurative spiritual sense was in Old English; the sense of "mental illumination" is first recorded mid-15c. Meaning "something used for igniting" is from 1680s. Meaning "a consideration which puts something in a certain view" (as in in light of) is from 1680s. Short for traffic light from 1938. Quaker use is by 1650s; New Light/Old Light in church doctrine also is from 1650s. Meaning "person eminent or conspicuous" is from 1590s. A source of joy or delight has been the light of (someone's) eyes since Old English:

Ðu eart dohtor min, minra eagna leoht [Juliana].

Phrases such as according to (one's) lights "to the best of one's natural or acquired capacities" preserve an older sense attested from 1520s. To figuratively stand in (someone's) light is from late 14c. To see the light "come into the world" is from 1680s; later as "come to full realization" (1812). The rock concert light-show is from 1966. To be out like a light "suddenly or completely unconscious" is from 1934.

light (adj.1)

"not heavy, having little actual weight," from Old English leoht (West Saxon), leht (Anglian), "not heavy, light in weight; lightly constructed; easy to do, trifling; quick, agile," also of food, sleep, etc., from Proto-Germanic *lingkhtaz (source also of Old Norse lettr, Swedish lätt, Old Frisian, Middle Dutch licht, German leicht, Gothic leihts), from PIE root *legwh- "not heavy, having little weight." The adverb is Old English leohte, from the adjective.

Meaning "frivolous" is from early 13c.; that of "unchaste" from late 14c., both from the notion of "lacking moral gravity" (compare levity). Of literature from 1590s. Light industry (1919) makes use of relatively lightweight materials. The notion in make light of (1520s) is "unimportance." Alternative spelling lite, the darling of advertisers, is first recorded 1962. Light horse "light armed cavalry" is from 1530s. Light-skirts "woman of easy virtue" is attested from 1590s. Lighter-than-air (adj.) is from 1887.

light (v.1)

"to touch down," as a bird from flight, "get down or descend," as a person from horseback, from Old English lihtan "to alight; to alleviate, make less heavy," from Proto-Germanic *linkhtijan, literally "to make light," from *lingkhtaz "not heavy" (see light (adj.1)). Apparently the etymological sense is "to dismount" (a horse, etc.), and thus relieve it of one's weight."

Alight has become the more usual word. To light on "happen upon, come upon" is from late 15c. To light out "leave hastily, decamp" is 1866, from a nautical meaning "move out, move heavy objects" (1841), a word of unknown origin but perhaps belonging to this word (compare lighter (n.1)).

light (v.2)

"to shed light; to set on fire," late Old English lihtan (Anglian), liehtan (West Saxon), originally transitive, "to ignite, set on fire," also in a spiritual sense, "to illuminate, fill with brightness." It is common Germanic (cognates: Old Saxon liohtian, Old High German liuhtan, German leuchten, Gothic liuhtjan "to light"), from the source of light (n.).

Meaning "furnish light for" is from c. 1200; sense of "emit light, shed light, shine" is from c. 1300. Buck writes that light is "much more common than kindle even with fire, and only light, not kindle, with candle, lamp, pipe, etc." To light up is from c. 1200 as "give light to" (a room, etc.); 1861 in reference to a pipe, cigar, etc. Related: Lighted; lighting.

light (adj.2)

"not dark," Old English leoht (West Saxon), leht (Anglian), "luminous, bright, beautiful, shining; having much light," from Proto-Germanic *leuhta- (source also of Old Saxon and Old High German lioht, Old Frisian liacht, German licht "bright"), from the source of Old English leoht (see light (n.)). Meaning "pale-hued" is from 1540s; prefixed to other color adjectives from early 15c. In earlier Middle English in reference to colors it meant "bright, vivid" (early 14c.).

updated on January 03, 2019

Definitions of light from WordNet
light (adj.)
marked by temperance in indulgence;
a light eater
a light smoker
ate a light supper
Synonyms: abstemious
light (adj.)
less than the correct or legal or full amount often deliberately so;
a light pound
Synonyms: scant / short
light (adj.)
of comparatively little physical weight or density;
magnesium is a light metal--having a specific gravity of 1.74 at 20 degrees C
a light load
light (adj.)
(used of color) having a relatively small amount of coloring agent;
light blue
a light-colored powder
light colors such as pastels
Synonyms: light-colored
light (adj.)
of the military or industry; using (or being) relatively small or light arms or equipment;
light weapons
light industry
light cavalry
light infantry
light (adj.)
not great in degree or quantity or number;
a light sentence
light snow was falling
light misty rain
casualties were light
light smoke from the chimney
a light accent
light (adj.)
psychologically light; especially free from sadness or troubles;
a light heart
light (adj.)
characterized by or emitting light;
the inside of the house was airy and light
a room that is light when the shutters are open
light (adj.)
(used of vowels or syllables) pronounced with little or no stress;
a syllable that ends in a short vowel is a light syllable
Synonyms: unaccented / weak
light (adj.)
easily assimilated in the alimentary canal; not rich or heavily seasoned;
a light diet
light (adj.)
(used of soil) loose and large-grained in consistency;
light soil
light (adj.)
(of sound or color) free from anything that dulls or dims;
a light lilting voice like a silver bell
Synonyms: clean / clear / unclouded
light (adj.)
demanding little effort; not burdensome;
light housework
light exercise
light (adj.)
of little intensity or power or force;
a light breeze
the light touch of her fingers
light (adj.)
(physics, chemistry) not having atomic weight greater than average;
light water is ordinary water
light (adj.)
weak and likely to lose consciousness;
light-headed from lack of sleep
light-headed with wine
felt light in the head
Synonyms: faint / swooning / light-headed / lightheaded
light (adj.)
very thin and insubstantial;
light summer dresses
light (adj.)
having little importance;
losing his job was no light matter
light (adj.)
intended primarily as entertainment; not serious or profound;
light verse
a light comedy
light (adj.)
silly or trivial;
light idle chatter
light banter
Synonyms: idle
light (adj.)
having relatively few calories;
Synonyms: lite / low-cal / calorie-free
light (adj.)
(of sleep) easily disturbed;
a light sleeper
in a light doze
Synonyms: wakeful
light (adj.)
casual and unrestrained in sexual behavior;
he was told to avoid loose (or light) women
Synonyms: easy / loose / promiscuous / sluttish / wanton
light (n.)
(physics) electromagnetic radiation that can produce a visual sensation;
the light was filtered through a soft glass window
Synonyms: visible light / visible radiation
light (n.)
any device serving as a source of illumination;
he stopped the car and turned off the lights
Synonyms: light source
light (n.)
a particular perspective or aspect of a situation;
although he saw it in a different light, he still did not understand
light (n.)
the quality of being luminous; emitting or reflecting light;
Synonyms: luminosity / brightness / brightness level / luminance / luminousness
light (n.)
an illuminated area;
he stepped into the light
light (n.)
a condition of spiritual awareness; divine illumination;
follow God's light
Synonyms: illumination
light (n.)
the visual effect of illumination on objects or scenes as created in pictures;
Synonyms: lightness
light (n.)
a person regarded very fondly;
the light of my life
light (n.)
having abundant light or illumination;
as long as the lighting was good
they played as long as it was light
Synonyms: lighting
light (n.)
mental understanding as an enlightening experience;
he finally saw the light
can you shed light on this problem?
light (n.)
merriment expressed by a brightness or gleam or animation of countenance;
Synonyms: sparkle / twinkle / spark
light (n.)
public awareness;
it brought the scandal to light
light (n.)
a visual warning signal;
there was a light at every corner
they saw the light of the beacon
light (n.)
a device for lighting or igniting fuel or charges or fires;
do you have a light?
Synonyms: lighter / igniter / ignitor
light (v.)
make lighter or brighter;
Synonyms: illume / illumine / light up / illuminate
light (v.)
begin to smoke;
After the meal, some of the diners lit up
Synonyms: light up / fire up
light (v.)
to come to rest, settle;
Misfortune lighted upon him
Synonyms: alight / perch
light (v.)
cause to start burning; subject to fire or great heat;
Synonyms: ignite
light (v.)
fall to somebody by assignment or lot;
Synonyms: fall
light (v.)
alight from (a horse);
Synonyms: unhorse / dismount / get off / get down
light (v.)
start or maintain a fire in;
Synonyms: fire / ignite
light (adv.)
with few burdens;
experienced travellers travel light
Synonyms: lightly
Light (n.)
a divine presence believed by Quakers to enlighten and guide the soul;
Synonyms: Inner Light / Light Within / Christ Within
Etymologies are not definitions. From, not affiliated with etymonline.