nano·​sec·​ond ˈna-nə-ˌse-kənd How to pronounce nanosecond (audio)
: one billionth of a second
: a very brief moment

Did you know?

The nonserious use of nanosecond is probably much more common than the proper technical use. In measurement terms such as nanosecond, nanogram, and nanometer, nano- means "billionth;" in other kinds of words, its meaning isn't quite so precise. In computers, the speed of reading and writing to random access memory (RAM) is measured in nanoseconds. By comparison, the speed of reading or writing to a hard drive or a CD-ROM player, or for information to travel over the Internet, is measured in milliseconds (thousandths of a second), which are a million times longer than nanoseconds.

Examples of nanosecond in a Sentence

It happens in less than a nanosecond. a nanosecond was about all that it took her to accept his marriage proposal
Recent Examples on the Web Still, having the option to choose the best player in the draft — or trade the pick for more assets — is something many executives would take in a nanosecond. Roderick Boone, Charlotte Observer, 11 May 2024 Magic Johnson answered his cell on the first ring and in a nanosecond his excitement was at a fever pitch. Broderick Turner, Los Angeles Times, 6 Apr. 2024 The programs will continue recognizing complex patterns, adapting faster to changing market conditions and adjusting trading strategies in nanoseconds. Atal Bansal, Forbes, 1 Mar. 2024 Given that polarons can last for about 11 nanoseconds, the scientists think that acoustic exciton-polarons could cover more than 25 micrometers before scattering. IEEE Spectrum, 6 Nov. 2023 Ground-penetrating radar waves travel at a fraction of the speed of light, so the entire process—transmission, reflection, recording—takes nanoseconds. WIRED, 28 Sep. 2023 After firing 192 lasers at a small pellet filled with deuterium-tritium fuel, the resulting reaction essentially created a tiny star for a few nanoseconds. Darren Orf, Popular Mechanics, 9 Aug. 2023 Side characters show up for a nanosecond, then fade from the film’s memory. David Fear, Rolling Stone, 23 June 2023 In any case, just to make things even less quibbling, suppose that the handoff to the human-in-the-loop occurred with a few nanoseconds left to go (a nanosecond is one billionth of a second, which by comparison a fast blink of the eye is a sluggish 300 milliseconds long). Lance Eliot, Forbes, 1 Aug. 2022

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'nanosecond.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


International Scientific Vocabulary

First Known Use

1958, in the meaning defined at sense 1

Time Traveler
The first known use of nanosecond was in 1958

Dictionary Entries Near nanosecond

Cite this Entry

“Nanosecond.” Dictionary, Merriam-Webster, Accessed 24 May. 2024.

Kids Definition


nano·​sec·​ond ˈnan-ə-ˌsek-ənd How to pronounce nanosecond (audio)
: one billionth of a second

Medical Definition


nano·​sec·​ond -ˌsek-ənd, -ənt How to pronounce nanosecond (audio)
: one billionth of a second
abbreviation ns, nsec
Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!