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

Example Sentences

Recent Examples on the Web Should the researchers’ initial promising results bear out, the millimeter-wave tech could inspire new applications based on a reliable and uninterrupted stream of heart health data. IEEE Spectrum, 4 Feb. 2022 While the paper, which claimed 5G millimeter waves can help colonize the coronavirus in the human body, was quickly retracted, that didn’t stop people from burning down 5G towers and harassing telecom engineers. Andrew Daniels, Popular Mechanics, 5 Jan. 2021 Those spectrum bands would enable the use of millimeter waves that could deliver faster, higher-quality video and multimedia content. Elena Malykhina, Scientific American, 22 Sep. 2016 Penzone included millimeter-wave scanners often used at airports as an example of what the department might use. Jose R. Gonzalez, The Arizona Republic, 12 Jan. 2023 But to reach the top speeds associated with 5G, carriers need millimeter-wave (or mmWave) technology, which takes advantage of the high end of the wireless spectrum, operating at 20 GHz and up. Klint Finley Joanna Pearlstein Simon Hill, WIRED, 31 Dec. 2022 One of the basic economic arguments for why CEO pay needs to be monarchically high is that the talent pool for would-be saviors is a millimeter deep. Matt Pearce, Los Angeles Times, 22 Nov. 2022 Braking duties are also handled by Shimano, courtesy of non-series dual-piston hydraulic calipers (with a 180 millimeter-diameter rotor up front), and Shimano even provides the Deore front hub with serviceable cup-and-cone bearings. James Huang, Outside Online, 25 Oct. 2022 Alamo Drafthouse, a national chain of cinemas with three locations in New York City, retains 35 millimeter in all its markets, according to its founder, Tim League. Ted Alcorn Evelyn Freja, New York Times, 23 Sep. 2022 See More

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

Word History


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

Dictionary Entries Near millimeter

Cite this Entry

“Millimeter.” Dictionary, Merriam-Webster, Accessed 31 Jan. 2023.

Kids Definition


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

Medical Definition


variants or chiefly British millimetre
: one thousandth of a meter
abbreviation mm

More from Merriam-Webster on millimeter

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