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 of split-second

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

That's because every possession demands rapid analysis such as reading the court, predicting opponents’ moves and making split-second decisions, all while maintaining control of the ball. —Daryl Austin, USA Today, 2 Nov. 2025

Goalkeeper Harlow Berger made a sliding, point-blank save in the box, but the rebound went right to a Cougar, who for a split-second had the entire net to shoot at. —Mike Cook, Twin Cities, 29 Oct. 2025

Noun

That’s roughly equal to about 887 kilograms of force (around 1,956 pounds of force), almost like having the weight of a small car slam into something in a split second. —MSNBC Newsweek, 28 Nov. 2025

According to the company, the M1 robot produces more than 10 kilowatts of power in one burst, equivalent to giving a human-sized machine the power of a motorcycle engine for a split second. —Atharva Gosavi, Interesting Engineering, 25 Nov. 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