Flash vs One second

When to use each in English, with meaning, register, and examples.

Flash

Top 2,000 (common)B2noun

One second

Top 2,000 (common)
 FlashOne second
Pronunciation🇬🇧 /["/flæʃ/"]/🇺🇸 /["/flæʃ/"]/🇬🇧 //wʌn ˈsɛk.ənd//🇺🇸 //wʌn ˈsɛk.ənd//
MeaningA sudden bright light or short burst of light.A very short amount of time.
ExampleThe flash of lightning illuminated the sky for a brief moment.Can you wait just one second?
RegisterNeutralNeutral
How commonTop 2,000 (common)Top 2,000 (common)
CEFR levelB2-
Part of speechnoun
Collocationsgreat, blinding, bright, experience, feel, have, erupt, illuminate something, light something, flash from, flash of, great, blinding, bright, experience, feel, have, erupt, illuminate something, light something, flash from, flash of, built-in, camera, use, go off, work, photography, with (a) flash, great, blinding, bright, experience, feel, have, erupt, illuminate something, light something, flash from, flash of, great, blinding, bright, experience, feel, have, erupt, illuminate something, light something, flash from, flash ofwait one second, take one second, in one second, spend one second
Antonymsdarkness, shadow-
Common mistakesConfused with 'splash' when describing water., Using 'flash' as a verb without specifying the subject., Overusing in formal contexts where other terms like 'illumination' may be more appropriate.Using 'seconds' instead of 'second' for a brief pause., Using it in entirely unrelated contexts, like long plans.
Usage notesUse 'flash' when referring to a quick and bright occurrence of light. It is informal in some contexts (e.g., a flash of inspiration) but can also be used in more formal language, like photography.Use in casual conversation when timing something for a brief period. Avoid in highly formal contexts.

See it in real clips

Flash
One second

Frequently asked questions: Flash vs One second

What's the difference between Flash and One second?

Flash: A sudden bright light or short burst of light. One second: A very short amount of time.

Can you show an example of each?

Flash: The flash of lightning illuminated the sky for a brief moment. One second: Can you wait just one second?

Can I use Flash and One second interchangeably?

Not always. Flash and One second are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.

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