split-second

1 of 2

adjective

split-sec·​ond ˈsplit-ˈse-kənd 

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

Adjective

• immediate
• instant
• instantaneous
• straightaway

Noun

• beat
• eyeblink
• flash
• heartbeat
• instant
• jiff
• jiffy
• minute
• moment
• nanosecond
• New York minute
• second
• shake
• trice
• twinkle
• twinkling
• wink

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

Adjective

But some in the community believe the knowledge that replay can fix their split-second decisions has become an unhealthy crutch for officials. —Chris Vannini, New York Times, 18 June 2025

Some of his photos took a split-second to capture, like the black caiman that poked its head out of the water to gobble up a passing bird. —Denny Lee, Travel + Leisure, 16 June 2025

Noun

For a split second, melting ice cream is dribbling down your own chin—and this is just one drink of many that evoke a specific experience. —Joseph Hernandez, Bon Appetit Magazine, 30 May 2025

Then, in a split second, Haliburton decided to dribble backward to hoist a prayer and go for the win. —James L. Edwards Iii, New York Times, 22 May 2025

Word History

First Known Use

Adjective

1944, in the meaning defined at sense 1

Noun

1912, in the meaning defined above

Rhymes for split-second

• beckoned
• reckoned
• second
• seconde
• femtosecond
• microsecond
• millisecond
• nanosecond
• picosecond

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