millisecond

noun

mil·​li·​sec·​ond ˈmi-lə-ˌse-kənd How to pronounce millisecond (audio)
-kənt
: one thousandth of a second

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A millisecond isn't long enough for the blink of an eye, but a few milliseconds may determine the winner of a swim race or a hundred-yard dash. With the ever-increasing speed of modern technology, even a millisecond has started to seem a little sluggish; computer operations are now measured in nanoseconds—that is, billionths of a second.

Examples of millisecond in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
But as Knight came with in a millisecond of pinning Reigns, the crowd turned. — Ryan Gaydos Outkick, FOXNews.com, 11 Oct. 2026 The difference between the 86,400 atomic seconds metric and a day measured by Earth’s rotation is less than 4 milliseconds. — Vahe Peroomian, The Conversation, 8 Oct. 2026 BirdVue uses millimeter-wave radar to detect a bird entering the detection area at millisecond speeds. — New Atlas, 8 Oct. 2026 The company says that if an agent attempts to move outside its software boundary, Sentry can quarantine and stop it in milliseconds. — Joshua Hong, Fortune, 4 Oct. 2026 See All Example Sentences for millisecond

Word History

Etymology

International Scientific Vocabulary

First Known Use

1909, in the meaning defined above

Time Traveler
The first known use of millisecond was in 1909

Rhymes for millisecond

See All Rhymes for millisecond

Browse Nearby Words

milliroentgen
millisecond
millisite
See all Nearby Words

Cite this Entry

“Millisecond.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/millisecond. Accessed 14 Oct. 2026.

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Kids Definition

millisecond

noun
mil·​li·​sec·​ond ˈmil-ə-ˌsek-ənd How to pronounce millisecond (audio)
also -ənt
: one thousandth of a second

Medical Definition

millisecond

noun
mil·​li·​sec·​ond ˈmil-ə-ˌsek-ənd, -ənt How to pronounce millisecond (audio)
: one thousandth of a second
—abbreviation ms, msec
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