split second

noun

1. a fraction of a second.
2. an infinitesimal amount of time; instant; twinkling.

split second

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

Other Words From

• split-second adjective

Word History and Origins

Origin of split second¹

First recorded in 1880–85

Idioms and Phrases

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]

Example Sentences

He said the officer had made "a split second decision on what he believed was necessary to protect his colleagues and to protect London".

From BBC

Created just a split second after the Big Bang, these hypothetical black holes would whip quietly through the solar system roughly once every few years, traveling over a hundred times faster than a bullet.

From Los Angeles Times

"Music is all time and no time at all. In the split second gap between sound being made and sound being heard, eternity ends."

From BBC

It took a split second for the instincts of Principal Laura Gutierrez to kick in when an earthquake coursed through Aldama Elementary School in Highland Park as she stood outside supervising recess.

From Los Angeles Times

For a split second, your mind considers the possibilities: A truck driving by?

From Los Angeles Times