There are 2 main definitions of flash in English:


Syllabification: flash
Pronunciation: /flaSH


1 [no object] (Of a light or something that reflects light) shine in a bright but brief, sudden, or intermittent way: the lights started flashing (as adjective flashing) a police car with a flashing light
More example sentences
  • I looked up at the bright green neon sign flashing on and off, ‘Club Divine’ it read.
  • A sudden burst of bright green light flashed behind the tree.
  • The ship whisked into the night's sky, its bright lights flashing.
1.1 [with object] Cause to shine briefly or suddenly: the oncoming car flashed its lights
More example sentences
  • The driver was alerted to on-coming cars flashing their lights at him.
  • The police car flashed his lights briefly at a car that touched 90 or so, but that was about it.
  • The car behind me started flashing its lights, and turned on its siren.
1.2 [with object] Shine or show a light to send (a signal): red lights started to flash a warning
More example sentences
  • The automobile in front of them flashed a warning signal of red to tell of slowing, and he eased up on the gas as he headed further into the dark city.
  • They want to install a system which will flash a warning signal in the cab of the train if it passes through a red light.
  • He lit the lamp he carried, and flashed an agreed signal to the other three men waiting in one of the canoes a short distance away.
1.3 [with object] Give (a swift or sudden look): Carrie flashed a glance in his direction [with two objects]: she flashed him a withering look
More example sentences
  • Brown flashed a knowing look into the gallery, and a few people, for want of a better word, tittered.
  • He flashed a stern look towards the nurse.
  • I flashed a look of gratitude at Noelle, and she nodded coolly.
1.4Express a sudden burst of emotion, especially anger, with a swift or sudden look: she glared at him, her eyes flashing
More example sentences
  • ‘Jordan isn't going to make me miserable,’ Faith argued, her eyes flashing with anger.
  • ‘Get the hell away from me Corey - right now’ Hailey said, her eyes flashing with anger.
  • His eyes were flashing with anger, but they softened.
2 [with object] Display (an image, words, or information) suddenly on a television or computer screen or electronic sign, typically briefly or repeatedly: suddenly the screen flashes a message
More example sentences
  • As he crossed the finishing line his image was flashed up on the large screens.
  • Your computer screen is flashing an unwelcome message.
  • The giant white screen flashed images of people in the streets mourning Corrie's death.
2.1 [no object] (Of an image or message) be displayed briefly or repeatedly on a screen: the election results flashed on the screen
More example sentences
  • I smiled and sat back watching as several images flashed across the screen, Matt still grunting in annoyance at not having found his desired station to watch.
  • He raised a scowl as his image flashed across the big screen.
  • A crackling image flashed onto the screen, lines of static and interference scrolled up and down the message.
2.2 informal Hold up or show (something, often proof of one’s identity) quickly before replacing it: she opened her purse and flashed her ID card
More example sentences
  • Ralphie responded quickly as he flashed them his press card.
  • Just then another passenger rose from his seat and flashed a small plastic card at the warring parties.
  • Jonathan flashed his ID, and the guards motioned the car through.
2.3 informal Make a conspicuous display of (something) so as to impress or attract attention: they all flash their money around
More example sentences
  • You should take their money if they are flashing it round.
  • They hate to see somebody flashing the money around like that.
  • He had a habit of flashing the wads of cash his benevolent son sent home to him.
2.4 [no object] (often as noun flashing) informal (Especially of a man) show one’s genitals briefly in public.
More example sentences
  • Believing a man had flashed at his girlfriend, he drove at him, jamming him against a wall.
  • A mother has warned other residents to be on their guard after a man flashed her 12-year-old daughter.
  • A bit later she was waving at me, and when I glanced over she flashed me again - and she'd taken her bra off!
3 [no object] Move or pass very quickly: a look of terror flashed across Kirov’s face the scenery flashed by another stray thought flashed through her mind
More example sentences
  • Eventually, I became aware that the streetlights were not flashing by as quickly as they had been.
  • The altimeter was counting down, the final couple of hundred feet flashing by too quickly.
  • The time flashed by so quickly for the rest of the trip.
informal belt, zap, bomb
3.1 [with object] Send (news or information) swiftly by means of telegraphy or telecommunications: the story was flashed around the world
More example sentences
  • Images of the shooting - videotaped by TV crews covering the march - were flashed around the world.
  • This news had earlier been flashed to the world via the BBC website.
  • However, the whole incident was flashed around to other bases, telling everyone to behave themselves.


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1A sudden brief burst of bright light or a sudden glint from a reflective surface: the grenade exploded with a yellow flash of light a lightning flash
More example sentences
  • At this a loud crash was heard behind them followed by a bright flash of lightning, lighting up the forest briefly.
  • As she was strolling down the final row, a sudden flash of bright light caught her attention.
  • Large flashes of light occasionally burst forth from the opening of a cave leading into the opposing mountain range.
2A thing that occurs suddenly and within a brief period of time, in particular.
2.1A sudden instance or manifestation of a quality, understanding, or humor: she had a flash of inspiration
More example sentences
  • His films, as a result, are often repulsive; yet they contain the occasional flash of genius that may redeem the more unpalatable aspects of his work.
  • Paul is manic and edgy on stage, with the occasional flash of surreal genius.
  • I won't say there was a sudden flash of insight but dimly I was becoming aware that there are lots of things to see if you take the time to look.
burst, outburst, wave, rush, surge, flush
2.2A news flash.
More example sentences
  • When at last the news agency flash came of the Nazi capitulation on May 7, 1945, the Manchester Eveneing News was ready.
  • I was in a of a press association this afternoon when the flash came in.
3 (Flash) Computing , trademark A platform for producing and displaying animation and video in web browsers.
More example sentences
  • We still do a lot of personal research and development work with Flash and our websites are really popular.
  • You'll need Flash and QuickTime to view all the extras buried in these online presentations.
  • The same brains that created the Internet have clearly mastered Flash as well.
4A camera attachment that produces a brief very bright light, used for taking photographs in poor light: an electronic flash if in any doubt, use flash [as modifier]: flash photography
More example sentences
  • Pulling out her camera and attaching the flash, she climbs out of the car and moves past the barricade.
  • The phone also is equipped with a camera featuring an attachable flash.
  • He finds Gilbert, and they spot Keaton, who is using the flash on her digital camera as a flashlight.
5Excess plastic or metal forced between facing surfaces as two halves of a mold close up, forming a thin projection on the finished object.
More example sentences
  • A rotary file in an electric drill motor is the perfect tool for grinding off flash.
  • The trailing edge smoothed out well and the excess plastic flash just fell off.
  • Also, when trimming the plates from the sprues, make sure you trim the flash from the bottom of the recessed tab to let the courses sit level.


informal , chiefly British Back to top  
1(Of a thing) ostentatiously expensive, elaborate, or up to date: a flash new car
More example sentences
  • It is simply the case that in this world of convenience, flash holidays and big cars, working the land has lost its appeal.
  • But the plan backfired when the driver couldn't get the flash car to start as they left the restaurant - leaving the couple at the mercy of the paparazzi.
  • This means that in a high-consumption society such as ours, when I buy a flash car or suit, I throw down the gauntlet to others to do likewise.
1.1(Of a person) superficially attractive because stylish and full of brash charm: he was carrying this money around and trying to be flash
More example sentences
  • They are big brash symbols of conspicuous consumption, a way for flash men and women with a lot of cash to flaunt their wealth.
  • Nicky Cole is a flash geezer from the South, but Yates is a flash geezer from the North.
  • It was a flash crowd, and soon our roofless concrete barn was packed with wet bodies, dancing under sheets of hard rain and the intermittent flashes of lightning.
2 archaic Of or relating to thieves, prostitutes, or the underworld, especially their language.
More example sentences
  • This is the story of an extraordinary quest by two women - one the wife of a journalist, and the other a young girl who had been sold to a flash house when she was just 10 years old.
  • Many British navy and army officers hated the 'flash language' used by convicts.
  • Notwithstanding the editor's condescension toward these ‘second-rate’ men, he recognizes the opportunity flash language provided for disguised communication.


Middle English (in the sense 'splash water about'): probably imitative; compare with flush1 and splash.


flash in the pan

A thing or person whose sudden but brief success is not repeated or repeatable: our start to the season was just a flash in the pan
[with allusion to the priming of a firearm, the flash arising from an explosion of gunpowder from the pan within the lock]
More example sentences
  • And his form so far this season has proved that his success last year was no flash in the pan.
  • It is not a flash in the pan but something that's been maintained over a long period.
  • Organising a music festival in India and battling the Indian bureaucracy was not exactly an easy affair for this group, but they seem confident about making this more than just a flash in the pan.

in (or like) a flash

Very quickly; immediately: she was out of the back door in a flash
More example sentences
  • I closed the door quickly and like a flash I was at the table filling my bag with the money once again.
  • They will sit on your rear bumper until they get a little bit of a straight road and then they are past you like a flash.
  • He was on to it like a flash, racing into the penalty area.
instantly, suddenly, abruptly, immediately, all of a sudden;
quickly, rapidly, swiftly, speedily;
in an instant/moment, in a (split) second, in a trice, in the blink of an eye
informal in a jiff, in a jiffy

(as) quick as a flash

(Especially of a person’s response or reaction) very quickly: quick as a flash, he was at her side
More example sentences
  • ‘You saved the best till last,’ replies the candidate, quick as a flash.
  • As quick as a flash, his eyes darted to Stevie, and he said: ‘Does that mean we have to call you Gerry now?’
  • She reveals she buys all her own clothes for work, ‘although I never pay full price,’ she adds, quick as a flash.

Phrasal verbs

flash back

(Of a person’s thoughts or mind) briefly and suddenly recall a previous time or incident: her thoughts immediately flashed back to last night
More example sentences
  • Suddenly my mind flashed back to a day eight months ago.
  • My mind immediately flashed back to my dream, and I blushed again.
  • My mind kept flashing back to what happened two weeks ago.

flash over

Make an electric circuit by sparking across a gap.
More example sentences
  • The theory here is that the primer flashes over the small powder charge and causes it to detonate.
  • An arc then flashes over between these electrodes 24 and 13, giving rise to ionization and pressurization.
  • If the voltage is high enough, the insulator flashes over causing a short circuit of the system.
(Of a fire) spread instantly across a gap because of intense heat.
More example sentences
  • Once the fire flashed over the side station, it quickly enveloped the deli restaurant, feeding on the combustible interior finishes and furnishings.
  • At about 4 p.m., the fire ‘flashed over’ and the buildings erupted in a mass of flame, trapping some staff on upper floors.
  • When the driver lifted the engine cover he provided the oxygen that was lacking and the fire ‘flashed over’ and spread quickly through the bus.

Definition of flash in:

There are 2 main definitions of flash in English:


Line breaks: flash

Entry from British & World English dictionary


A water-filled hollow formed by subsidence, especially any of those due to rock salt extraction in or near Cheshire: sandpits and flashes also attract visiting birds


Middle English (in the sense 'a marshy place'): from Old French flache, variant of Picard and Norman dialect flaque, from Middle Dutch vlacke. The current sense dates from the late 19th century.

Definition of flash in: