mil·​li·​me·​ter | \ ˈmi-lə-ˌmē-tər How to pronounce millimeter (audio) \
variants: US millimeter or British millimetre

Definition of millimeter

: a unit of length equal to ¹/₁₀₀₀ meter — see Metric System Table

Examples of millimeter in a Sentence

Recent Examples on the Web

The three Samsung phones tested by the Tribune — the Galaxy S8, Galaxy S9 and Galaxy J3 — were positioned at 10 or 15 millimeters from the body, the distances chosen by the company in accordance with FCC guidelines. Sam Roe,, "We tested popular cellphones for radiofrequency radiation. Now the FCC is investigating.," 21 Aug. 2019 There’s also a gel cushioning system that helps shock absorption during impact, and a midsole with 3 millimeters of additional height to relieve any tension in the Achilles. Braelyn Wood,, "Reese Witherspoon Owns So Many Pairs of These Sneakers That She's Constantly Wearing Them," 23 July 2019 The vast majority of bots in use in warehouses and factories today are only able to perform rote tasks, planned in advance down to the millimeter. James Vincent, The Verge, "Boston Dynamics prepares to launch its first commercial robot: Spot," 5 June 2019 Luhman essentially ruled out the existence of anything bigger and warmer than a gas giant with a 2014 analysis of infrared data, but physicists expect a smaller, colder Planet Nine to shine in the millimeter part of the spectrum. Quanta Magazine, "Why Can’t We Find Planet Nine?," 3 July 2018 That means that a tiny spark of just 1 millimeter would be 3,000 volts. Rhett Allain, WIRED, "The Physics of Falling Magnets in Stranger Things Season 3," 9 Aug. 2019 Tardigrades, which are no longer than 1 millimeter, live in water or in the film of water on plants like lichen or moss. Cnn, The Mercury News, "Are tardigrades alive on the moon after spacecraft’s crash landing?," 7 Aug. 2019 Now able to print ultrafine details 0.02 millimeter across, the researchers printed a whole collagen heart equivalent to that of a newborn infant, complete with ventricles, veins and arteries. Scientific American, "Fang Needles, Quantum Carpets and Tender Robot Touches," 2 Aug. 2019 In July specifically, Ruth Mottram of the Danish Meteorological Institute writes on Twitter, Greenland’s ice sheet lost 197 billion tons of water, or enough to raise sea levels by 0.5 millimeters over a one-month period. Meilan Solly, Smithsonian, "Greenland Lost 12.5 Billion Tons of Ice in a Single Day," 1 Aug. 2019

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.

See More

First Known Use of millimeter

1797, in the meaning defined above

History and Etymology for millimeter

French millimètre, from milli- + mètre meter

Keep scrolling for more

Learn More about millimeter

Dictionary Entries near millimeter








Statistics for millimeter

Last Updated

27 Aug 2019

Look-up Popularity

Time Traveler for millimeter

The first known use of millimeter was in 1797

See more words from the same year

Keep scrolling for more

More Definitions for millimeter



English Language Learners Definition of millimeter

: a length equal to 1/1000 meter


mil·​li·​me·​ter | \ ˈmi-lə-ˌmē-tər How to pronounce millimeter (audio) \

Kids Definition of millimeter

: a unit of length equal to 1/1000 meter


variants: or chiefly British millimetre \ ˈmil-​ə-​ˌmēt-​ər How to pronounce millimetre (audio) \

Medical Definition of millimeter

: one thousandth of a meter abbreviation mm

Keep scrolling for more

More from Merriam-Webster on millimeter

Rhyming Dictionary: Words that rhyme with millimeter

Spanish Central: Translation of millimeter

Nglish: Translation of millimeter for Spanish Speakers

Britannica English: Translation of millimeter for Arabic Speakers

Comments on millimeter

What made you want to look up millimeter? Please tell us where you read or heard it (including the quote, if possible).


readily or continually undergoing change

Get Word of the Day daily email!

Test Your Vocabulary

Musical Words Quiz

  • gramophone
  • Which word describes a musical performance marked by the absence of instrumental accompaniment?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!