English Reference

Word

flash

US/ˈfɫæʃ/

UK/flˈæʃ/

Definitions

01burst of light

A2 · Elementary Countable noun

n. a sudden, brief, and bright light.

n. a sudden and brief emission of light, often intense in nature.

“A flash of lightning lit up the dark sky for a second.”

“The sudden flash of the explosion was visible from several miles away, momentarily blinding the observers.”

Synonyms

02photography

B1 · Intermediate Uncountable noun Photography

n. a small light on a camera that makes a bright burst to help take photos in the dark.

n. an electronic device or bulb used in photography to produce a brief, intense light for illumination.

“Don't use the flash in the museum because it might damage the old paintings.”

“The photographer adjusted the external flash to bounce the light off the ceiling, creating a softer effect for the portrait.”

Synonyms

03a short moment

B1 · Intermediate Countable noun

n. a very short period of time.

n. an extremely brief interval of time; often used in the phrase 'in a flash'.

“The summer holidays seemed to go by in a flash.”

“The entire sequence of events occurred in a flash, leaving the witnesses struggling to recall the exact order of the accident.”

04sudden idea or feeling

B2 · Upper Intermediate Countable noun

n. a sudden and powerful thought or emotion.

n. a sudden and brilliant burst of an abstract quality, such as wit, genius, or insight.

“I had a flash of inspiration and finally solved the puzzle.”

“In a rare flash of genius, the engineer proposed a solution that bypassed the structural limitations of the original design.”

05to shine briefly

B1 · Intermediate

v. to shine with a bright light for a very short time.

v. to emit a brief or intermittent light; can be transitive or intransitive.

“The lighthouse flashed its warning across the stormy sea.”

“The diamond flashed brilliantly as she moved her hand under the gallery spotlights.”

06to move quickly

B2 · Upper Intermediate

v. to move very fast past someone or something.

v. to move at great speed in a specified direction.

“A red sports car flashed past us on the motorway.”

“The high-speed train flashed through the station without stopping, creating a powerful gust of wind on the platform.”

Synonyms

Antonyms

07to show quickly

B2 · Upper Intermediate

v. to show something to someone very quickly.

v. to make something visible for a very brief duration, often to prove identity or status.

“The officer flashed his badge and asked to enter the building.”

“He flashed a quick smile of encouragement before stepping onto the stage to begin his presentation.”

Synonyms

08computing

C1 · Advanced Computing Technical

v. to update the software on a piece of hardware, like a phone or computer part.

v. to overwrite or update the firmware in a non-volatile memory chip.

“You need to flash the latest BIOS to support the new processor.”

“The technician warned that if the power failed while flashing the firmware, the device could become permanently unusable.”

Synonyms

updatereprogram

09showy or expensive

B2 · Upper Intermediate British English · Informal

adj. looking expensive and impressive, often in a way that tries to get attention.

adj. ostentatiously expensive or stylish; intended to impress others.

“He drives a flash car but he doesn't have much money in the bank.”

“The new nightclub was a bit too flash for my taste, with gold-plated fixtures and overpriced cocktails.”

Antonyms

Collocations

Common phrases and expressions where native English speakers use the word “flash” in context.

Verb

01. flash a smile

“She flashed a quick smile at the audience before starting her presentation.”

verb + noun

Adjective

02. blinding flash

“A blinding flash of lightning lit up the entire sky for a split second.”

adj + noun

03. brief flash

“I saw a brief flash of recognition in her eyes when I mentioned his name.”

adj + noun

Noun

04. camera flash

“The bright camera flash made everyone blink during the group photo.”

noun + noun

05. flash of anger

“He felt a sharp flash of anger when he realized they had lied to him.”

noun + of + noun

06. flash of inspiration

“The solution came to her in a sudden flash of inspiration while she was jogging.”

noun + of + noun

07. news flash

“We interrupt this program for a special news flash regarding the election results.”

noun + noun

Preposition

08. in a flash

“Don't worry about the mess; I'll have the kitchen cleaned up in a flash.”

prep + noun

Real-World Examples

“If you have deeper sleep after using antihistamines, perhaps hot flashes won’t wake you up during the night, and your mood could be better the next day, she says.”
The Guardian 14 Aug 2026
“In some smoke-affected thunderstorms , positive flashes accounted for more than 40% of all cloud-to-ground lightning.”
The Conversation 30 Jul 2026
“Researchers believe both died at the same time, possibly during a flash flood or mudslide.”
ScienceDaily 30 Jul 2026

Etymology

In some senses, from Middle English flasshen, a variant of flasken, flaskien (“to sprinkle, splash”), which was likely of imitative origin; in other senses probably of North Germanic origin akin to Swedish dialectal flasa (“to burn brightly, blaze”), related to flare. Compare also Icelandic flasa (“to rush, go hastily”).

From Middle English flashe, flaske, also found as flosche and flushe (whence modern English flosh and flush), used in Middle and modern English for bodies of water with varying emphasis on them being "pools" or "marshes". It is not entirely clear whether these constitute a single term with varied spellings, or have distinct etymologies. The form flash, flashe is often suggested to be from Old French flache, French flaque, which is of Germanic origin, akin to Middle Dutch vlacke (“an estuary, flats with stagnant pools”). See flush for more on that form.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Word family

ADJECTIVE

Related words

Idioms

The word in film

The Flash · 2015 · Action

Directed by:
David Nutter
Starring:
Wentworth Miller, Tom Felton, Grant Gustin

Grant Gustin stars as a superhero who gains the ability to travel at incredible speeds after a freak accident. This action series follows his adventures as he uses his power to move quickly through the city to fight crime and save lives.

The Flash · 2023 · Action

Directed by:
Andy Muschietti
Starring:
Ben Affleck, Jeremy Irons, Michael Keaton

Director Andy Muschietti brings this DC Comics superhero to the big screen, focusing on his superhuman ability to travel at incredible speeds. The title describes how the character can move across the world in an instant to fight crime and change the past.

Domains

ComputingEngineeringLinguisticsMilitaryPhotography

This entry

Exam level
CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.B2 FirstIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.5.5–6.5TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 4.0–4.572–94TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.785–944
Frequency
Common
Level
B2 · Upper IntermediateOxford
Updated

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