split-second

1 of 2

adjective

split-sec·​ond ˈsplit-ˈse-kənd How to pronounce split-second (audio)
Synonyms of split-secondnext
1
: occurring in a split second
a split-second decision
2
: extremely precise
split-second timing

split second

2 of 2

noun

: a fractional part of a second : flash

Synonyms of split-second

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Adjective

Noun

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Examples of split-second in a Sentence

Adjective a day trader who is used to making split-second decisions Noun In a split second, it was all over. a devastating accident can cause everything in your life to change in a split second
Recent Examples on the Web
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Adjective
An onboard neural network then parsed through all that in real time, making split-second decisions on the best routes to fly. — Mack Degeurin, Popular Science, 14 Oct. 2026 Of course, the full tray of decadent foods between the driver’s hands and the steering wheel would make taking control difficult in a split-second emergency. — Joe Wilkins, Futurism, 14 Oct. 2026
Noun
Scientists have recorded what happens inside a crystal in the split second before a quantum bit forms. — Aman Tripathi, Interesting Engineering, 7 Oct. 2026 The emotions of Chiefs fans changed in a split second Sunday. — Pete Grathoff, Kansas City Star, 5 Oct. 2026 See All Example Sentences for split-second

Word History

First Known Use

Adjective

1944, in the meaning defined at sense 1

Noun

1912, in the meaning defined above

Time Traveler
The first known use of split-second was in 1912

Rhymes for split-second

See All Rhymes for split-second

Browse Nearby Words

split screen
split-second
split second
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Cite this Entry

“Split-second.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/split-second. Accessed 19 Oct. 2026.

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Kids Definition

split second

1 of 2 noun
: a small fraction of a second : flash

split-second

2 of 2 adjective
1
: occurring in a split second
a split-second decision
2
: extremely precise
split-second timing
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