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.
Each millimeter-sized TRISO particle consists of a High-Assay Low-Enriched Uranium (HALEU) core surrounded by three specialized layers that serve distinct physical functions. — Aman Tripathi, Interesting Engineering, 23 July 2026 Bone must be separated from surrounding rock millimeter by millimeter with a pneumatic chisel, whose needle gently breaks away rock while ultraviolet light reveals where the bone ends and the surrounding rock begins. — ABC News, 22 July 2026 The project involves millimeter-by-millimeter removal of twelve layers of decades-old paint, according to Artnet. — News Desk, Artforum, 22 July 2026 There is a small margin for error of around 3 millimeters, though the mark Džumhur said was the one left by Arnaldi’s serve appeared to be further out than that. — James Hansen, New York Times, 20 July 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 26 Jul. 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

More from Merriam-Webster on millimeter

Nglish: Translation of millimeter for Spanish Speakers

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