flash
flash — verb
1. to give out a sudden bright light that lasts only a moment, or to cause a light
to give out a sudden bright light that lasts only a moment, or to cause a light source to produce such a burst of light
At midnight, lightning flashed across the dark sky, briefly lighting up the whole valley.
Eli flashed the torch into the cave to see if anyone was hiding there.
transitive: flash + object (torch, light)
Red warning lights flashed on the control panel during the storm.
A passing car flashed its headlights to warn the driver about the accident ahead.
transitive with possessive: flash + its + noun
- flash brightly
- flash on and off
- flash a light
- lightning flashes
- warning lights flash
- fade
to lose brightness gradually rather than shine suddenly
Grammar Patterns
flash (intransitive)
flash + noun phrase (transitive)
Usage Note
The transitive form means 'to cause something to shine briefly' (Eli flashed the torch), while the intransitive form means 'to shine briefly on its own' (Lights flashed).
2. if someone's eyes or face flash with a feeling, the emotion becomes suddenly vis
if someone's eyes or face flash with a feeling, the emotion becomes suddenly visible through their expression
Rania's eyes flashed with anger when she heard the unfair criticism of her work.
intransitive: eyes flash with emotion
A warm smile flashed across Hui's face as she opened the carefully wrapped gift.
The old man's eyes flashed with pride while watching his granddaughter collect her award.
Élise's expression flashed a clear warning that made the children stop arguing at once.
transitive use: expression flashes a warning
- eyes flash with anger
- eyes flash with pride
- smile flashes across face
- expression flashes a warning
Grammar Patterns
eyes/face + flash + with + emotion
Usage Note
The subject must be the eyes, face, or expression — not the person. 'She flashed with anger' would be understood literally as emitting light, not showing emotion.
Common Mistakes
3. to travel or pass by a place with great speed, often too fast to see clearly
to travel or pass by a place with great speed, often too fast to see clearly
A deer suddenly flashed across the road just in front of our moving car.
The racing boats flashed past the finish line one after another.
intransitive: flash past/across/through + direction
Heloísa watched the birds flash among the trees in the early morning light.
The express train flashed through the small country station without making any stop.
- flash across
- flash past
- flash through
- flash by
- crawl
to move extremely slowly
Grammar Patterns
flash + adverb/preposition of direction
Usage Note
Almost always followed by a preposition of direction (across, past, through, by, among). The verb itself only provides the speed; the preposition gives the path.
Common Mistakes
4. to show something to someone for a very short period, often as proof of identity
to show something to someone for a very short period, often as proof of identity or access
The security guard flashed a fake ID card at the entrance and walked straight past.
Christopher quickly flashed his ticket at the gate before running to catch his train.
transitive: flash + object + at + person/location
The reporter flashed a photo of the ceremony on the screen for just two seconds.
Sahil flashed a warm smile at the shy new student sitting alone in the corner.
collocation: flash a smile
- flash a ticket
- flash a card
- flash a badge
- flash an ID
- flash a smile
Grammar Patterns
flash + noun phrase + at/to + person
Usage Note
The object is typically a ticket, ID, badge, card, or smile — items that can be seen and recognized in an instant. Distinguish from sense 9 (verb), where the display has a boastful or attention-seeking purpose.
Common Mistakes
5. to intentionally show one's sexual organs in a public space, which is a criminal
to intentionally show one's sexual organs in a public space, which is a criminal offence
The man was arrested after witnesses reported that he flashed at people in the park.
A new law increases the penalty for anyone who flashes in public places.
intransitive: flash + at + location/people
Police are looking for a suspect who reportedly flashed near the shopping centre this week.
The court ordered the man to register as a sex offender after he was found guilty of flashing.
legal context: found guilty of flashing
- flash at someone
- charged with flashing
- arrested for flashing
- indecent exposure
the legal term; a noun phrase, not a verb
Grammar Patterns
flash (intransitive)
flash + at + person (intransitive)
flash + object + to + person (transitive)
6. to send information or a signal rapidly, especially by using light, radio waves,
to send information or a signal rapidly, especially by using light, radio waves, or an electronic system
The two ships flashed signals to each other across the dark stretch of water.
Naoko flashed the news to her team through the office messaging system.
transitive: flash + object + to + recipient through + medium
The old lighthouse still flashes a warning light every fifteen seconds for passing ships.
Hyun flashed a quick message to his manager before the meeting started.
- flash a signal
- flash a message
- flash the news
- flash a warning
- withhold
to keep information back
Grammar Patterns
flash + noun phrase + to + recipient
flash + noun phrase + through/across + medium
Usage Note
Often used with a prepositional phrase indicating the recipient (to + person) or the medium (through/across/via + system). In modern use, can refer to electronic messaging.
7. If a thought, idea, or memory flashes through your mind, it comes to you suddenl
If a thought, idea, or memory flashes through your mind, it comes to you suddenly and unexpectedly.
A terrible thought flashed through Zola's mind as she listened to the news.
flash + through [someone's] mind — sudden arrival of a thought
It flashed across Élise's mind that she had left the oven on at home.
flash + across [someone's] mind + that-clause
The answer to the puzzle suddenly flashed into Christopher's head during lunch.
Memories of summer holidays flashed through Yuki's mind as she opened the photo album.
A warning signal flashed across the driver's mind just before the accident.
- flash through [someone's] mind
- flash across [someone's] mind
- flash into [someone's] head
- cross one's mind
softer, less urgent — 'it crossed my mind that...' suggests a passing thought without the suddenness
- occur to
more neutral and common in writing — 'it occurred to me that...'
- spring to mind
used when an example or answer comes readily, not necessarily suddenly
Grammar Patterns
flash + through/across [someone's] mind
flash + into [someone's] head
Usage Note
Subject must be a thought, idea, memory, or similar mental content — never a person. This is the only sense of 'flash' that patterns naturally with a that-clause.
Common Mistakes
8. to appear or become visible suddenly, often for only a very short time before di
to appear or become visible suddenly, often for only a very short time before disappearing again.
A message from Dr. Sivan flashed onto the screen while Tomás was checking his email.
flash + onto [screen] — sudden appearance on a display
The face of an old friend flashed onto the screen during the video call.
A message from Minh flashed up on the phone while Sari was cooking dinner.
flash + up on — notification appearing suddenly
Images of the storm damage flashed across the television every few minutes.
The outline of the mountain flashed into sight through a sudden break in the clouds.
flash + into sight — sudden visibility after being hidden
- flash across [surface/space]
- flash onto [screen]
- flash past [someone/something]
- flash up on [display]
- appear suddenly
direct and neutral, but lacks the speed sense of 'flash'
- pop up
informal — used for notifications, windows, or unexpected arrivals
- flicker
suggests unsteady light, not a single sudden appearance
Grammar Patterns
flash + adverb/preposition (across, onto, past, up)
Usage Note
Usually takes a prepositional phrase indicating direction (across, onto, past, up). The subject is typically a moving object, image, or light — not a person.
Common Mistakes
9. to proudly show something valuable, expensive, or impressive in order to attract
to proudly show something valuable, expensive, or impressive in order to attract attention or admiration — for example, flashing a new watch, a wad of cash, or a winning smile.
Eli could not stop flashing his new watch at everyone in the office.
flash + [object] + at [someone] — showing off
Kian flashed a pile of cash at the bar just to impress his friends.
The magazine cover flashed photos of celebrities who were wearing diamond jewellery at the event.
flash + photos/images — media displaying proudly
Leo walked into the party and immediately flashed his award-winning smile at the crowd.
Instead of hiding her exam results, Eleni flashed the certificate at everyone she met.
- flash [something] at [someone]
- flash a smile
- flash cash
Grammar Patterns
flash + noun + at [someone]
Usage Note
Carries a mildly negative or critical tone — suggests the person is trying too hard to impress. Can also be used playfully ('She flashed him a bright smile').
Common Mistakes
flash — noun
1. A sudden strong light that appears and then disappears in a very short time.
A sudden strong light that appears and then disappears in a very short time.
A flash of lightning lit up the whole garden for a brief moment.
collocation: flash of lightning
Leo saw a bright flash coming from behind the old factory wall.
The flash from the explosion was visible for miles around the empty valley.
There was a sudden flash, and then everything went completely dark.
common pattern: there was a sudden flash
The hiker covered his eyes when the flash of the fireworks filled the night sky.
- flash of lightning
- flash of light
- bright flash
- sudden flash
- darkness
the complete absence of light
Grammar Patterns
flash + of + noun (light, lightning)
Usage Note
Frequently paired with 'of' followed by a light source — lightning, sunlight, headlights, torchlight. The light source is usually natural or accidental, not controlled by a person.
Common Mistakes
2. A strong feeling, thought, or idea that appears in your thoughts very suddenly,
A strong feeling, thought, or idea that appears in your thoughts very suddenly, without any warning.
Tanvi felt a flash of anger when she saw the unfair remark online.
collocation: a flash of anger
A sudden flash of understanding helped Beatrix solve the difficult puzzle.
Heloísa had a flash of inspiration while washing the dishes after dinner.
collocation: a flash of inspiration
A flash of memory helped the old man recall his visit to the coastal town.
A flash of recognition crossed Femi's face when he heard the familiar voice.
- flash of anger
- flash of inspiration
- flash of recognition
- flash of understanding
Grammar Patterns
a flash of + emotion/feeling/thought
Usage Note
Often followed by 'of + abstract noun' (anger, inspiration, panic, hope, recognition). The noun is usually a strong emotion or a cognitive event. Distinguish from sense 1: here there is no actual light — the experience is mental or emotional, not visual.
Common Mistakes
3. The part of a camera that creates a short bright light, allowing you to take pho
The part of a camera that creates a short bright light, allowing you to take photos in dark places.
Daichi turned on the camera flash before taking a photo of the dark room.
collocation: camera flash / turn on the flash
Most mobile phones now have a built-in flash for nighttime photography.
Aylin's photo came out too bright because the flash was accidentally left on.
The wedding photographer used an external flash to get the right lighting indoors.
collocation: external flash
The reporter switched off the flash to take quiet pictures during the court hearing.
- camera flash
- built-in flash
- external flash
- turn on the flash
- flash photography
- flashgun
a separate, more powerful flash unit used by professional photographers
- strobelight
a light that produces very fast, repeated flashes, used in studios or clubs
Usage Note
Countable (a flash / two flashes) when referring to a specific device or unit. Uncountable when referring to the system or technology in general ('This camera has excellent flash' / 'Shoot with flash'). 'Flash' as uncountable has no article.
Common Mistakes
4. A small coloured cloth patch or badge on a uniform indicating the wearer's rank
A small coloured cloth patch or badge on a uniform indicating the wearer's rank or military group.
The officer wore a red flash on his sleeve to show his high rank.
collocation: wear a flash on [clothing]
Each unit in the army uses a different coloured flash on the shoulder.
Liam sewed the new rank flash onto his jacket before the morning inspection.
The blue flash on her collar identified her as a member of the medical corps.
- rank flash
- shoulder flash
- sleeve flash
- coloured flash
- uniform flash
Grammar Patterns
flash + on + clothing
Usage Note
This sense is strongly tied to military and formal uniform contexts. Outside the military, the same word is used for decorative coloured strips on clothing or book covers. In Taiwan, this may be compared to rank badges (階級章) on military uniforms.
Common Mistakes
5. A very quick look at someone or something, lasting only a moment and often not s
A very quick look at someone or something, lasting only a moment and often not showing the whole thing.
Sofie caught a quick flash of the fox as it ran across the road ahead.
pattern: catch a flash of
From the speeding train, Lien saw a flash of the ocean between two hills.
Mira caught a flash of movement in the corner of her eye and turned around.
The child had only a flash of the clown before it disappeared behind the curtain.
- catch a flash of
- flash of movement
- quick flash
- stare
a long, fixed look — the opposite of a brief instant
Grammar Patterns
a flash of + noun
catch/get a flash of
Usage Note
Common in the phrase 'catch a flash of' (see/hear for an instant). The object is usually something moving or partially hidden. This sense overlaps with 'glimpse' but emphasises even greater brevity. The word 'flash' itself does not mean 'look' — the brief sight is what makes it a flash.
Common Mistakes
6. A short burst of light that is used to send a message or to attract someone's at
A short burst of light that is used to send a message or to attract someone's attention, especially across a distance or in an emergency.
The ship sent out flashes of light to warn other boats of the danger ahead.
collocation: send out flashes of light
Christopher used a torch to send flashes to the rescue team on the other side.
The lighthouse sends out regular flashes that guide ships away from the rocks.
A single flash from the control tower told the pilot the runway was clear ahead.
The sailor saw a flash in the distance and knew the rescue boat had arrived.
- flash of light
- send a flash
- warning flash
- signal flash
Grammar Patterns
send out flashes
flash + of + light
Usage Note
This sense focuses on intentional communication using light, not accidental light (sense 1) or camera use (sense 3). The signal can be a single flash (one short burst) or a sequence of flashes forming a code such as Morse code.
Common Mistakes
7. A short piece of urgent news that interrupts regular television or radio program
A short piece of urgent news that interrupts regular television or radio programmes, or appears as a notification on a phone or computer.
A news flash interrupted the evening programme to report the earthquake in Japan.
compound noun: 'news flash' for urgent broadcasts
Antonia received a flash notification on her phone about the airport closure.
compound noun: 'flash notification' on digital devices
The channel broadcast a flash alert when the wildfire reached Oakridge.
Dewi saw a flash on her screen announcing the election results.
- news flash
- flash alert
- flash notification
- broadcast a flash
- flash on screen
Usage Note
Frequently used in compound nouns: 'news flash', 'flash alert', 'flash notification'. Unlike regular news items, a flash is typically brief and signals something important enough to interrupt ongoing content.
Common Mistakes
8. An interval that is almost too fast to notice, frequently appearing in expressio
An interval that is almost too fast to notice, frequently appearing in expressions such as 'in a flash' to indicate something done or gone in an instant.
Reema finished her drink in a flash and ran out the door.
'in a flash' — the most common idiom for this sense
The hummingbird darted past the window in a flash of green and blue.
In a flash, the child disappeared into the busy market crowd.
The summer holidays went by in a flash, and soon September arrived.
'went by in a flash' — pattern for time passing quickly
Karim solved the puzzle in a flash, surprising everyone at the table.
- in a flash
- quick as a flash
- gone in a flash
- over in a flash
- instant
more formal and often used in technical or poetic contexts
- moment
slightly longer than a flash; less dramatic
- blink of an eye
an idiomatic alternative with the same meaning
Usage Note
Almost always appears in fixed phrases with 'in a' or 'in one': 'in a flash', 'quick as a flash'. Unlike sense 2 (SUDDEN EXPERIENCE), this sense focuses purely on the brevity of time, not on the emotional or mental content of the moment.
Common Mistakes
9. An attractive outward appearance that is designed to get people's attention, but
An attractive outward appearance that is designed to get people's attention, but often without real quality or lasting value underneath.
The new restaurant had more flash than flavour — the food was disappointing.
'more flash than [substance]' — common contrastive pattern
Otis bought a cheap watch that was all flash and no reliability.
'all flash and no [quality]' — typical negative idiom
The advertisement relied on flash rather than facts to sell the product.
Yael's presentation was all flash — bright graphics with very little data.
- all flash
- more flash than something
- flash and no substance
- rely on flash
- showiness
slightly more formal; names the quality rather than the thing itself
- glamour
can be positive or neutral; flash is always critical
- ostentation
formal term for showy display meant to impress
Usage Note
Carries a negative or critical tone. Frequently paired with contrasting nouns like 'substance', 'quality', 'reliability', or 'facts' to emphasise the gap between appearance and reality. Distinguished from sense 7 (NEWS REPORT) and sense 8 (BRIEF MOMENT) by its evaluative, informal register.
Common Mistakes
a flash in the pan
idiomA sudden success that only lasts for a very short time and is unlikely to happen again.
The band's first album was a huge hit, but they turned out to be a flash in the pan.
Many critics thought the actor would have a long career, but his early success was just a flash in the pan.
Very quickly; in a very short amount of time.
The cat saw the dog and disappeared into the bushes in a flash.
Quick as a flash, the child ran across the street to grab the ball.
in/like a flash
idiomHappening extremely fast or suddenly.
The fireworks display was over in a flash.
Like a flash, Maya remembered where she left her keys.
Moving or reacting extremely fast.
Quick as a flash, the cat caught the mouse.
Brian answered the question quick as a flash.
flash — adjective
1. expensive or brightly coloured so as to catch people's notice, but often conside
expensive or brightly coloured so as to catch people's notice, but often considered to show poor taste.
Xiu arrived at the party wearing a flash gold dress that caught everyone's attention.
attributive use: flash + gold dress
The salesman's flash suit made customers wonder if they could trust him.
Lukas bought a flash new sports car but could not afford the insurance.
collocation: flash new [noun]
The restaurant was too flash for Shanti's simple family birthday dinner.
predicative use with 'too flash'
Critics said the flash gold decorations on the building showed poor taste.
- flash car
- flash suit
- flash watch
- flash hotel
- flash new
- too flash
- a bit flash
- flashy
more common in American English; can be neutral or slightly negative
- showy
broader meaning, not limited to expense; can describe behaviour too
- gaudy
stronger negative tone; suggests something is cheap or vulgarly bright
- ostentatious
formal register; implies deliberate display of wealth or status
- plain
simple, with no decoration or attempts to attract attention
- understated
elegant in a quiet, subtle way — considered a compliment
Grammar Patterns
flash + noun (attributive)
be/look/seem + flash (predicative)
Usage Note
Frequently used to describe cars, clothes, accessories, and buildings. The word carries a mildly critical tone — calling something 'flash' suggests the speaker finds it too showy or lacking in elegance.
Common Mistakes
Word family
- flashyadjectiveB2
- flashilyadverbC1
- flashinessnounC1
- flashedadjectiveB2
- flashingadjectiveB2
- flashingnounC1
- flashlightnounA2
- flashbacknounC1
- flashpointnounC1
- flashcardnounA2
- flashbulbnounB2
- flashgunnounC1
- newsflashnounB1
Synonym discussion
Sense: verb/1
All five describe light, but they differ sharply. Flash (B2) is the only one that means 'a sudden, brief burst of light from a source' — lightning flashes, a camera flashes. Gleam (B2) describes a soft, steady light shining from a polished surface, often reflected; a car's polished bonnet gleams in the sun, but it does not flash. Glint (C1) is a tiny, quick spark of reflected light, usually from a small object — a glint of sunlight off a watch face or a knife blade; it is smaller and shorter than a gleam. Flare (B2) is a sudden, bright, often growing light, usually a flame — a match flares up, then burns steadily; it lasts longer than a flash and involves heat. Sparkle (B2) is a series of tiny, dancing points of light, like a diamond or stars on a clear night; it is continuous and scattered, not a single burst. In practice: 'The lighthouse sent out a quick flash every ten seconds' (a single burst from a source). 'Her diamond ring sparkled under the restaurant lights' (many tiny reflections). 'The cat's eyes gleamed in the dark' (steady reflected light).
Common collocations
Nouns
- flash of lightning
- flash of light
- flash of anger
- flash of inspiration
- flash of recognition
- news flash
- camera flash
- flash notification
- flash smile
Adverbs
- suddenly flash
- briefly flash
- quickly flash
- flash brightly
Phrases
- in a flash
- quick as a flash
- a flash in the pan
- flash in the pan
- all flash and no substance
- more flash than [quality]
Prepositions
- flash across
- flash past
- flash through
- flash [object] at [person]
- flash with [emotion]
Etymology
From Middle English flashen (meaning 'to dash, splash, or sprinkle water'), probably originating from an imitative Germanic root suggesting sudden or forceful movement. The original sense of liquid motion shifted in the 1500s to light emission — the visual parallel being a sudden, brief burst, like water catching sunlight as it splashes. A separate strand of meaning, 'to dash or move violently,' influenced the speed-related senses (MOVE FAST). The adjective and noun senses meaning 'showy' or 'showy display' emerged in the late 19th century, extending the idea of eye-catching brightness into social behaviour. Cognate with Middle Dutch flasschen and Middle Low German flasen, both carrying the 'splash' meaning.