split second

American  

noun

1. a fraction of a second.

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

---

split second British  

noun

1. an extremely small period of time; instant

---

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]

---

Other Word Forms

• split-second
  adjective

---

Etymology

Origin of split second

First recorded in 1880–85

---

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 job of the orbiting receivers now was to determine in a split second which of Aurich’s variations would work in that particular scenario.

From The Wall Street Journal ● Oct. 6, 2026

And then he got James McCann to hit a soft grounder up the middle, but McCann beat second baseman Tommy Edman’s throw to first by a split second.

From Los Angeles Times ● Aug. 9, 2026

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

From BBC ● Jun. 13, 2026

I try reaching for the boat, but it’s gone in a split second, gone so fast it might as well not even exist at all.

From "Hurricane Child" by Kheryn Callender

Random Word

Spin the wheel and learn a new word!

---

Related Words

• blink of an eye
• millisecond
• nanosecond

---