ki·​lo·​me·​ter | \ kə-ˈlä-mə-tər How to pronounce kilometer (audio) , ki-; ˈki-lə-ˌmē-tər How to pronounce kilometer (audio) , ˈkē-lə- \

Definition of kilometer

: a metric unit of length equal to 1000 meters — see Metric System Table

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How do you pronounce kilometer?: Usage Guide

In North American speech kilometer is most often pronounced with primary stress on the second syllable. This pronunciation is also heard frequently in British speech. Those who object to second syllable stress say that the first syllable should be stressed in accord with the stress patterns of centimeter, millimeter, etc. However, the pronunciation of kilometer does not parallel that of other metric compounds. From 1828 to 1841 Noah Webster indicated only second syllable stress, and his successor added a first syllable stress variant in the first Merriam-Webster dictionary of 1847. Thus, both pronunciations are venerable. Most scientists use second syllable stress, although first syllable stress seems to occur with a higher rate of frequency among scientists than among nonscientists.

Did You Know?

A kilometer is equal to about 62/100 of a mile, and a mile is equal to about 1.61 kilometers. The U.S. has been slow to adopt metric measures, which are used almost everywhere else in the world. Though our car speedometers are often marked in both miles and kilometers, the U.S. and Great Britain are practically the only developed nations that still show miles rather than kilometers on their road signs. But even in the U.S., footraces are usually measured in meters or kilometers, like the Olympic races. Runners normally abbreviate kilometer to K: "a 5K race" (3.1 miles), "the 10K run" (6.2 miles), and so on.

Examples of kilometer in a Sentence

Recent Examples on the Web Ingenuity’s flights will require Perseverance to find a flat location, somewhere picked by the helicopter team within a 10-day-drive of the landing site, says Trosper, or up to one kilometer away—with the rover able to travel about 100 meters a day. Jonathan O'callaghan, Scientific American, "The First 100 Days on Mars: How NASA’s Perseverance Rover Will Begin Its Mission," 18 Feb. 2021 The approximately 3-square-kilometer (square-mile) compound of warehouses, loading bays, wholesale outlets and parking lots is the main depot for getting fruit, vegetables and other produce to about 20 million consumers in the metropolitan area. Lissette Romero, Star Tribune, "Amid virus surge, life goes on at Mexico City's main market," 8 Dec. 2020 Boonstra was in third place after 2 miles and didn’t take the lead until the final kilometer on her way to a seven-second win over Grace Christian’s Megan Nelson. Beth Bragg, Anchorage Daily News, "Merchant claims third straight Division II state cross-country title in blazing fashion," 11 Oct. 2020 For every kilometer down into the Earth’s crust, temperatures rise about 25°C. Michael J. Coren, Quartz, "Geothermal energy, the forgotten renewable, has finally arrived," 20 Dec. 2020 This would make chondrules a key stepping-stone from miniscule dust to larger kilometer-sized planetesimals. Jonathan O'callaghan, Scientific American, "Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation," 8 Dec. 2020 The hole, scientists believe, ultimately penetrates more than half a kilometer into the ice, joining a network of channels extending all the way to the base of the ice sheet. Chris Mooney, Anchorage Daily News, "Scientists descended into Greenland’s perilous ice caverns - and came back with a worrying message," 23 Dec. 2020 That’s more than one barrier for every mile of river (or 0.74 barriers per kilometer). Stefan Lovgren, Environment, "European rivers are littered with barricades, but a movement grows to remove them," 17 Dec. 2020 Radio astronomers also hope for progress on the Square Kilometer Array, an international project aiming to amass a square kilometer of data-collecting area by joining thousands of smaller dishes in the deserts of South Africa and Australia. Charlie Wood, Popular Science, "The Arecibo Observatory collapsed this week. What now?," 4 Dec. 2020

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

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First Known Use of kilometer

1810, in the meaning defined above

History and Etymology for kilometer

French kilomètre, from kilo- + mètre meter

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Time Traveler for kilometer

Time Traveler

The first known use of kilometer was in 1810

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Statistics for kilometer

Last Updated

27 Feb 2021

Cite this Entry

“Kilometer.” Dictionary, Merriam-Webster, Accessed 28 Feb. 2021.

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More Definitions for kilometer



English Language Learners Definition of kilometer

: a unit of length equal to 1,000 meters


ki·​lo·​me·​ter | \ ki-ˈlä-mə-tər How to pronounce kilometer (audio) , ˈki-lə-ˌmē-tər \

Kids Definition of kilometer

: a metric unit of length equal to 1000 meters


variants: or chiefly British kilometre \ ˈkil-​ə-​ˌmēt-​ər How to pronounce kilometer (audio) , kə-​ˈläm-​ət-​ər How to pronounce kilometer (audio) \

Medical Definition of kilometer

: 1000 meters

More from Merriam-Webster on kilometer

Nglish: Translation of kilometer for Spanish Speakers

Britannica English: Translation of kilometer for Arabic Speakers

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