See more synonyms for light on
verb (used without object), light·ed or lit, light·ing.
  1. to get down or descend, as from a horse or a vehicle.
  2. to come to rest, as on a spot or thing; fall or settle upon; land: The bird lighted on the branch. My eye lighted on some friends in the crowd.
  3. to come by chance; happen; hit (usually followed by on or upon): to light on a clue; to light on an ideal picnic spot.
  4. to fall, as a stroke, weapon, vengeance, or choice, on a place or person: The choice lighted upon our candidate.
Verb Phrases
  1. light into, Informal. to make a vigorous physical or verbal attack on: He would light into anyone with the slightest provocation.
  2. light out, Slang. to leave quickly; depart hurriedly: He lit out of here as fast as his legs would carry him.

Origin of light

before 900; Middle English lihten, Old English līhtan to make light, relieve of a weight; see light2 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for light on

dock, settle, berth, alight, thump, pilot, debark, disembark, ditch, steer, ground

British Dictionary definitions for light on


  1. God regarded as a source of illuminating grace and strength
  2. Quakerism short for Inner Light


  1. the medium of illumination that makes sight possible
  2. Also called: visible radiation electromagnetic radiation that is capable of causing a visual sensation and has wavelengths from about 380 to about 780 nanometres
  3. (not in technical usage) electromagnetic radiation that has a wavelength outside this range, esp ultraviolet radiationultraviolet light
  4. the sensation experienced when electromagnetic radiation within the visible spectrum falls on the retina of the eyeRelated prefix: photo-
  5. anything that illuminates, such as a lamp or candle
  6. See traffic light
  7. a particular quality or type of lighta good light for reading
    1. illumination from the sun during the day; daylight
    2. the time this appears; daybreak; dawn
  8. anything that allows the entrance of light, such as a window or compartment of a window
  9. the condition of being visible or known (esp in the phrases bring or come to light)
  10. an aspect or viewhe saw it in a different light
  11. mental understanding or spiritual insight
  12. a person considered to be an authority or leader
  13. brightness of countenance, esp a sparkle in the eyes
    1. the act of igniting or kindling something, such as a cigarette
    2. something that ignites or kindles, esp in a specified manner, such as a spark or flame
    3. something used for igniting or kindling, such as a match
  14. See lighthouse
    1. the effect of illumination on objects or scenes, as created in a picture
    2. an area of brightness in a picture, as opposed to shade
  15. a poetic or archaic word for eyesight
  16. the answer to a clue in a crossword
  17. in light of or in the light of in view of; taking into account; considering
  18. light at the end of the tunnel hope for the ending of a difficult or unpleasant situation
  19. out like a light quickly asleep or unconscious
  20. see the light
    1. to gain sudden insight into or understanding of something
    2. to experience a religious conversion
  21. see the light or see the light of day
    1. to come into being
    2. to come to public notice
  22. shed light on or throw light on to clarify or supply additional information on
  23. stand in a person's light to stand so as to obscure a person's vision
  24. strike a light
    1. (verb)to ignite something, esp a match, by friction
    2. (interjection) Britishan exclamation of surprise
  1. full of light; well-lighted
  2. (of a colour) reflecting or transmitting a large amount of lightlight yellow Compare medium (def. 2), dark (def. 2)
  3. phonetics relating to or denoting an (l) pronounced with front vowel resonance; clearthe French "l" is much lighter than that of English See dark (def. 9)
verb lights, lighting, lighted or lit (lɪt)
  1. to ignite or cause to ignite
  2. (often foll by up) to illuminate or cause to illuminate
  3. to make or become cheerful or animated
  4. (tr) to guide or lead by light
See also lights 1, light up
Derived Formslightish, adjectivelightless, adjective

Word Origin for light

Old English lēoht; related to Old High German lioht, Gothic liuhath, Latin lux


  1. not heavy; weighing relatively little
  2. having relatively low densitymagnesium is a light metal
  3. lacking sufficient weight; not agreeing with standard or official weights
  4. not great in degree, intensity, or numberlight rain; a light eater
  5. without burdens, difficulties, or problems; easily borne or donea light heart; light work
  6. graceful, agile, or deftlight fingers
  7. not bulky or clumsy
  8. not serious or profound; entertaininglight verse
  9. without importance or consequence; insignificantno light matter
  10. frivolous or capricious
  11. loose in morals
  12. dizzy or uncleara light head
  13. (of bread, cake, etc) spongy or well leavened
  14. easily digesteda light meal
  15. relatively low in alcoholic contenta light wine
  16. (of a soil) having a crumbly texture
  17. (of a vessel, lorry, etc)
    1. designed to carry light loads
    2. not loaded
  18. carrying light arms or equipmentlight infantry
  19. (of an industry) engaged in the production of small consumer goods using light machineryCompare heavy (def. 10)
  20. aeronautics (of an aircraft) having a maximum take-off weight less than 5670 kilograms (12 500 pounds)
  21. chem (of an oil fraction obtained from coal tar) having a boiling range between about 100° and 210°C
  22. (of a railway) having a narrow gauge, or in some cases a standard gauge with speed or load restrictions not applied to a main line
  23. bridge
    1. (of a bid) made on insufficient values
    2. (of a player) having failed to take sufficient tricks to make his contract
  24. phonetics prosody (of a syllable, vowel, etc) unaccented or weakly stressed; shortCompare heavy (def. 13) See also light 1 (def. 30)
  25. phonetics the least of three levels of stress in an utterance, in such languages as English
  26. light on informal lacking a sufficient quantity of (something)
  27. make light of to treat as insignificant or trifling
  1. a less common word for lightly
  2. with little equipment, baggage, etcto travel light
verb lights, lighting, lighted or lit (lɪt) (intr)
  1. (esp of birds) to settle or land after flight
  2. to get down from a horse, vehicle, etc
  3. (foll by on or upon) to come upon unexpectedly
  4. to strike or fall onthe choice lighted on me
Derived Formslightish, adjectivelightly, adverblightness, noun

Word Origin for light

Old English lēoht; related to Dutch licht, Gothic leihts
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for light on



"to illuminate, fill with brightness," Old English lyhtan, common Germanic (cf. Old Saxon liohtian, Old High German liuhtan, German leuchten, Gothic liuhtjan "to light"), from source of from light (n.). Related: Lighted; lighting.



"not dark," Old English leoht, common Germanic (cf. 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.



"brightness, radiant energy," Old English leht, earlier leoht "light, daylight; luminous, beautiful," from West Germanic *leukhtam (cf. Old Saxon lioht, Old Frisian liacht, Middle Dutch lucht, Dutch licht, Old High German lioht, German Licht, Gothic liuhaþ "light"), from PIE *leuk- "light, brightness" (cf. 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").

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 (e.g. in light of) is from 1680s. Something that's a joy and a delight has been the light of (someone's) eyes since Old English:

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

To see the light "come into the world" is from 1680s; later in a Christian sense.



"not heavy," from Old English leoht "not heavy, light in weight; easy, trifling; quick, agile," from Proto-Germanic *lingkhtaz (cf. Old Norse lettr, Swedish lätt, Old Frisian, Middle Dutch licht, German leicht, Gothic leihts), from PIE root *legwh- "not heavy, having little weight" (cf. Latin levis "light," Old Irish lu "small;" see lever).

The notion in make light of (1520s) is of "unimportance." Alternative spelling lite, the darling of advertisers, is first recorded 1962. The adverb is Old English leohte, from the adjective. Light-skirts "woman of easy virtue" is attested from 1590s. To make light of is from 1520s.



"touch down," from Old English lihtan "to alight; alleviate, leave," from Proto-Germanic *linkhtijan, literally "to make light," from *lingkhtaz "not heavy" (see light (adj.1)). Apparently the ground sense is "to dismount a horse, etc., and thus relieve it of one's weight." To light out "leave hastily" is 1870, from a nautical meaning "move out, move heavy objects," of unknown origin but perhaps belonging to this word (cf. lighter (n.1)).

Online Etymology Dictionary, © 2010 Douglas Harper

light on in Medicine


  1. Electromagnetic radiation that has a wavelength in the range from about 4,000 (violet) to about 7,700 (red) angstroms and may be perceived by the normal unaided human eye.
  2. Electromagnetic radiation of any wavelength.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

light on in Science


  1. Electromagnetic radiation that can be perceived by the human eye. It is made up of electromagnetic waves with wavelengths between 4 X 10-7 and 7 X 10-7 meters. Light, and all other electromagnetic radiation, travels at a speed of about 299,728 km (185,831 mi) per second in a vacuum. See also photon.
  2. Electromagnetic energy of a wavelength just outside the range the human eye can detect, such as infrared light and ultraviolet light. See Note at electromagnetic radiation.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

light on in Culture


The type of electromagnetic wave that is visible to the human eye. Visible light runs along a spectrum from the short wavelengths of violet to the longer wavelengths of red. (See photon.)

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Idioms and Phrases with light on

light on

Also, light upon. Happen upon, come across, discover. For example, John was delighted to light on a new solution to the problem, or We were following the path when suddenly we lit upon a cave. [Second half of 1400s]


In addition to the idioms beginning with light

  • light a fire under
  • light as a feather
  • light at the end of the tunnel
  • light dawned, the
  • lighten up
  • light heart
  • light into
  • lightning never strikes twice in the same place
  • light on
  • light out
  • light up

also see:

  • begin to see daylight (see the light of day)
  • bring to light
  • come to light
  • go light on
  • green light
  • heavy (light) heart
  • hide one's light
  • in a good (bad) light
  • in the cold light of day
  • in the light of
  • lace (light) into
  • leading light
  • make light of
  • many hands make light work
  • once over lightly
  • out cold (like a light)
  • see the light
  • shed light on
  • sweetness and light
  • travel light
  • trip the light fantastic
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.