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

Simple Definition of kilometer

  • : a unit of length equal to 1,000 meters

Source: Merriam-Webster's Learner's Dictionary

Full Definition of kilometer

  1. :  a metric unit of length equal to 1000 meters

  2. — see metric system table

Usage Discussion of kilometer

In No. 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.

Origin and Etymology of kilometer

French kilomètre, from kilo- + mètre meter

First Known Use: 1810

Other Weights and Measures Terms

KILOMETER Defined for Kids


noun ki·lo·me·ter \ki-ˈlä-mə-tər, ˈki-lə-ˌmē-tər\

Definition of kilometer for Students

  1. :  a metric unit of length equal to 1000 meters

Medical Dictionary


noun ki·lo·me·ter

Medical Definition of kilometer

  1. :  1000 meters

Variants of kilometer

or chiefly British


\ˈkil-ə-ˌmēt-ər, kə-ˈläm-ət-ər\play play

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