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

With inflation squeezing their margins and rideshare platforms demanding a large share of their earnings, a driver’s split-second decision to accept a fare is a high-stakes calculation of business survival. — Christopher S. Tang, The Conversation, 8 July 2026

Each robot must independently interpret ball position and goalkeeper movement before committing to a strike, making split-second corrections based on sensor feedback. — Jijo Malayil, Interesting Engineering, 24 June 2026

Noun

But the real challenge – and the reason no bird-scale robot has managed this leap before – is the split second in between, when the robot has to shove itself out of the water with nothing but its wings. — New Atlas, 13 July 2026

Yes, the teenager hasn’t impressed as much as other superstars at this tournament, but that could change in a split second. — Ben Church, CNN Money, 10 July 2026

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