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

• instantaneous
• immediate
• instant

Noun

• minute
• second
• moment
• heartbeat

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

Much of the controversy surrounds how the play is officiated, with the Eagles’ offensive line often getting a split-second head start on the snap. —Saad Yousuf, New York Times, 19 Oct. 2025

Released on the occasion of the Singapore Grand Prix, the choice of the HMC 804 automatic flying tourbillon movement, with its double hairspring designed to improve precision and resilience, is a nod to the split-second accuracy demanded in Formula One. —Carol Besler, Robb Report, 3 Oct. 2025

Noun

And for that split second the ball hung in the air after the back-of-the-rim miss, the Lakers were justified in that thought. —Dieter Kurtenbach, Mercury News, 22 Oct. 2025

Charles Lee pondered his answer for a split second. —Roderick Boone, Charlotte Observer, 18 Oct. 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