split second

American  

noun

1. a fraction of a second.

2. an infinitesimal amount of time; instant; twinkling.

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split second British  

noun

1. an extremely small period of time; instant

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adjective

1. made or arrived at in an infinitely short time

   a split-second decision

2. depending upon minute precision

   split-second timing

split second Idioms  

1. An instant, a fraction of a second, as in Our best swimmer came in a split second before theirs. This expression alludes to a stop watch that has two second hands, one above the other, for timing more than one athlete or intervals of a race by a single athlete. Each hand can be stopped independently of the other, so a second can be “split” when one second hand stops a fraction of a second after the other. [c. 1880]

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Other Word Forms

• split-second
  adjective

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Etymology

Origin of split second

First recorded in 1880–85

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Example Sentences

See Examples For:

split second

But that split second fortifies Morrison, confirming that his quest to Everest is for everyone that he’s lost, and every heartstopping moment along the way.

From Salon ● Nov. 1, 2026

The confrontation between the two lasts only a split second, because the man with the dogs steps back after tossing the canister, and the agent confronting him lets up.

From Los Angeles Times ● Oct. 30, 2026

In a split second, he says, something crossed his path – something he still cannot explain.

From BBC ● Jun. 13, 2026

For very small particles, the entire event lasts only a split second before the material completely burns up.

From Science Daily ● May 14, 2026

Even in the split second of the event I could see the flies.

From "Woodsong" by Gary Paulsen

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Related Words

• blink of an eye
• millisecond
• nanosecond

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