kilometer

noun

ki·​lo·​me·​ter kə-ˈlä-mə-tər 

ki-;

ˈki-lə-ˌmē-tər 

ˈkē-lə-

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

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

Since early January, astronomers have used the Magdalena Ridge Observatory in New Mexico, the Danish Telescope and the Very Large Telescope in Chile to track the asteroid, which is currently 28 million miles (45 million kilometers) from Earth and moving farther away over time, Farnocchia said. —Ashley Strickland, CNN, 31 Jan. 2025

This led to the discovery of a hitherto unknown region of Io that's subject to extreme volcanism across 40,000 square miles (100,00 square kilometers). —Robert Lea, Space.com, 31 Jan. 2025

She was born and raised in Celle, a village in Lower Saxony, just a few kilometers from the infamous Bergen-Belsen concentration camp where Anne Frank died. —Larry Luxner, Sun Sentinel, 30 Jan. 2025

Each train is designed to accommodate over 400 passengers and will operate at speeds reaching up to 350 kilometers per hour (217 mph). —Jonathan Granoff, Newsweek, 29 Jan. 2025

Word History

Etymology

French kilomètre, from kilo- + mètre meter

First Known Use

1810, in the meaning defined above

Kids Definition

kilometer

noun

ki·​lo·​me·​ter kə-ˈläm-ət-ər  kil-ˈäm- 

ˈkil-ə-ˌmēt-ər

: a metric unit of length equal to 1000 meters see metric system

Medical Definition

kilometer

noun

ki·​lo·​me·​ter

variants or chiefly British kilometre

ˈkil-ə-ˌmēt-ər  kə-ˈläm-ət-ər 

: 1000 meters