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
Locating and directing this mission requires extreme precision down to the nanosecond, errors in navigation which could risk spacecraft entering the wrong orbits.
From BBC • Apr. 3, 2024
If they faced inside the chain, they would repel each other, forcing the molecule to fly apart in a nanosecond.
From "The Gene" by Siddhartha Mukherjee
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.
