millimeter

noun

mil·​li·​me·​ter ˈmi-lə-ˌmē-tər How to pronounce millimeter (audio)
variants US millimeter or British millimetre
: a unit of length equal to 1/1000 meter see Metric System Table

Examples of millimeter 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.
Their current fibers measure about 1 millimeter across, but improved fabrication methods could reduce that thickness to tens of micrometers. — Aamir Khollam, Interesting Engineering, 9 Oct. 2026 BirdVue uses millimeter-wave radar to detect a bird entering the detection area at millisecond speeds. — New Atlas, 8 Oct. 2026 Elsewhere, Basquiat printed the same screen twice, moving it only a few millimeters between impressions. — Daniel Cassady, ARTnews.com, 7 Oct. 2026 Prosecutors said Flynn kept a 9-millimeter handgun in the center console of his truck, which was found open and empty when police arrived at the scene. — Nancy Dillon, Rolling Stone, 5 Oct. 2026 See All Example Sentences for millimeter

Word History

Etymology

French millimètre, from milli- + mètre meter

First Known Use

1797, in the meaning defined above

Time Traveler
The first known use of millimeter was in 1797

Rhymes for millimeter

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Browse Nearby Words

millime
millimeter
millimetric
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Cite this Entry

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

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Kids Definition

millimeter

noun
mil·​li·​me·​ter ˈmil-ə-ˌmēt-ər How to pronounce millimeter (audio)
: a measure of length equal to ¹⁄₁₀₀₀ meter see metric system table

Medical Definition

millimeter

noun
mil·​li·​me·​ter
variants or chiefly British millimetre
ˈmil-ə-ˌmēt-ər How to pronounce millimeter (audio)
: one thousandth of a meter
—abbreviation mm
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