nanosecond
Americannoun
noun
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The term is often used to refer to a very short time: “He missed having an accident by nanoseconds.”
Etymology
Origin of nanosecond
Explanation
There are one billion nanoseconds in one second. In other words, a nanosecond is one billionth of a second. Even a blink lasts longer than that. One nanosecond compares to a second the same way one second compares to 31.71 years. It's such a tiny amount of time that it's almost impossible to imagine. Some scientists call a nanosecond a "light foot," since light can travel approximately one foot in one nanosecond. You can also use this word figuratively, to mean "a really short length of time." Nano- comes from the Greek root nanos, "a dwarf."
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
A nanosecond is the time it takes for light to travel about one foot.
From The Wall Street Journal • Dec. 16, 2025
The first half of the show unpacks the sensory systems that leads people to experience flavor in a nanosecond.
From Salon • Dec. 9, 2024
The intense beams will allow researchers to image samples at nanometer scales and take snapshots of chemical reactions over nanosecond time frames.
From Science Magazine • Nov. 27, 2024
Time is currently measured on Earth by hundreds of atomic clocks stationed around our planet which measure the changing energy state of atoms to record time to the nanosecond.
From BBC • Apr. 3, 2024
Kids like Ross Wilcox'd say, “What's this then, Taylor?” snap off its pendulum in a nanosecond, and say, “Shoddy workmanship, that.”
From "Black Swan Green" by David Mitchell
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
