nano·​sec·​ond | \ˈna-nə-ˌse-kənd, -kənt\

Definition of nanosecond 

1 : one billionth of a second

2 : a very brief moment

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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

Hands were suspended in the air after each piece, dropping for the next work after a nanosecond, preventing applause and creating two seamless program halves. Peter Dobrin,, "Pianist András Schiff is a master of detail at the Kimmel," 1 Apr. 2018 Those pulses have to be generated by something, and a good signal generator might update its output every nanosecond. Chris Lee, Ars Technica, "New form of qubit control may yield longer computation times," 25 Jan. 2018 Even if the differences cancel each other out on the scale of seconds or minutes, small fluctuations could make the clock less effective on a millisecond or nanosecond scale. Avery Thompson, Popular Mechanics, "Here Is the World's Most Stable Atomic Clock," 28 Nov. 2016 Ytterbium is highly stable, so ytterbium atomic clocks are accurate past the nanosecond scale, all the way to the picosecond and femtosecond scale (1/1,000,000,000,000,000th of a second). Avery Thompson, Popular Mechanics, "Here Is the World's Most Stable Atomic Clock," 28 Nov. 2016 Being able to trade at the nanosecond level is vital to Nasdaq. John Markoff, New York Times, "Time Split to the Nanosecond Is Precisely What Wall Street Wants," 29 June 2018 Abloh is planning much more symbolism that will send his very visible, very people-friendly message of inclusion around the internet in nanoseconds as the audience takes their seats at 2pm Paris time. Sarah Mower, Vogue, "Virgil Abloh Talks Louis Vuitton: “I Want a Young Generation to Know, Hey, There’s Someone Here Who’s Listening”," 21 June 2018 No one should have questioned for a nanosecond that this sensitive information would go straight to the White House, anyway. Elizabeth Drew, The New Republic, "Trump’s Saturday Night Massacre Has Already Begun," 5 June 2018 After going normcore for a nanosecond, indulging in some Versace archival moments, and even—gasp!—wearing sweats and leggings, the star pulled out all the stops yesterday with three wardrobe changes. Janelle Okwodu, Vogue, "Of Course Lady Gaga Wore 3 Runway Looks in 24 Hours," 25 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'nanosecond.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of nanosecond

1958, in the meaning defined at sense 1

History and Etymology for nanosecond

International Scientific Vocabulary

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Last Updated

31 Oct 2018

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The first known use of nanosecond was in 1958

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English Language Learners Definition of nanosecond

: one billionth of a second

: a very short time


nano·​sec·​ond | \-ˌsek-ənd, -ənt \

Medical Definition of nanosecond 

: one billionth of a second abbreviation ns, nsec

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