ki·lo·me·ter | \kə-ˈlä-mə-tər, ki-;ˈki-lə-ˌmē-tər \

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

The world’s fastest hunter—the peregrine falcon—snatches prey out of the sky at speeds of more than 300 kilometers per hour. Katie Langin, Science | AAAS, "Peregrine falcons maneuver best when dive-bombing at more than 300 kilometers per hour," 12 Apr. 2018 With so many hazards and intersections on the route, the speed limit at the site is about 20 to 25 kilometers an hour. Kyunghee Park,, "Singapore Built a Dedicated Town for Self-Driving Buses," 4 June 2018 Tuesday’s flat leg with its four-kilometer finish — the longest straightaway to conclude a leg on this Tour— was perfect terrain for the budding rivals to break the tie. Joseph Wilson, The Seattle Times, "Gaviria beats Sagan again to claim 2nd Tour win on Stage 4," 10 July 2018 Qualification had taken more than two years, 884 days to be precise, and saw them visit 22 different countries, traveling more than 250,000 kilometers in the process. CNN, "How Australia used wearable technology to negotiate 250,000 kilometer World Cup journey," 6 June 2018 The station is currently orbiting between 201 and 221 kilometers in altitude, descending about 4 kilometers per day, according to Harvard-Smithsonian astrophysicist Jonathan McDowell. Jay Bennett, Popular Mechanics, "Tiangong-1 Space Station to Fall Out of Sky as Soon as This Week," 26 Mar. 2018 People have fled about 570 homes near a 2-square-mile (6-square-kilometer) fire that started Friday west of Colorado Springs. Fox News, "Wind spreads California fire as other states battle blazes," 3 July 2018 The only crashing Romanenko did was at the Seaport Village finish-line tape, winning the 1 kilometer swim, 30K bike and 10K run in 1 hour, 34 minutes, 6 seconds. Don Norcross,, "Third time’s a charm for Romanenko at S.D. International Triathlon," 24 June 2018 The company promises a future of large imaging arrays, kilometer-scale communications tools, and big space stations all built off-planet by smart robots. Joe Pappalardo, Popular Mechanics, "Smart Robots Are the Secret to Spaceflight's Future," 15 June 2018

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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Statistics for kilometer

Last Updated

13 Oct 2018

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Time Traveler for kilometer

The first known use of kilometer was in 1810

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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, 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, kə-ˈläm-ət-ər \

Medical Definition of kilometer 

: 1000 meters

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Comments on kilometer

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


to reject or criticize sharply

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