kilometer

[ ki-lom-i-ter, kil-uh-mee‑ ]

noun

1. a unit of length, the common measure of distances equal to 1,000 meters, and equivalent to 3280.8 feet or 0.621 mile. : km

kilometer

/ kĭ-lŏm′ĭ-tər,kĭl′ə-mē′tər /

1. A unit of length in the metric system equal to 1,000 meters (0.62 mile).
2. See Table at measurement

kilometer

1. In the metric system , one thousand meters , or about five-eighths of a mile.

Pronunciation Note

The usual pronunciation for units of measurement starting with kilo-, as kilocalorie, kiloliter, and kilohertz, as well as for units of length ending in the base word meter, as centimeter, hectometer, and millimeter, gives primary stress to the first syllable and secondary to the third. It would seem logical for kilometer to follow this pattern, and in fact the pronunciation [kil, -, uh, -mee-ter] has been used since the early 1800's. A second pronunciation: [ki-, lom, -i-ter], with stress on the second syllable only, was first recorded in America before 1830. Although often criticized on the basis of analogy, this pronunciation has persisted in American English, increasing in frequency, and has gained popularity in British English as well. It is reinforced by words for instruments (rather than units) of measurement ending in -meter, as thermometer, barometer, and speedometer, having stress on the -om syllable. Both pronunciations are used by educated speakers, including members of the scientific community.

Other Words From

• kil·o·met·ric [kil-, uh, -, me, -trik], kilo·metri·cal adjective

Word History and Origins

Origin of kilometer¹

First recorded in 1800–10; from French kilomètre; kilo-, meter ¹

Example Sentences

But a northern population of beaked hazelnuts revealed something surprising: five distinct genetic subgroups, four of which could be traced to far-flung locations across British Columbia, some 800 kilometers away.

From Science Magazine

Beginning in early 2025, researchers plan to deploy thousands of instruments and drill holes to record-setting depths, all with the goal of creating a 3D map of the rock layers kilometers below the surface.

From Science Magazine

In 2019, almost 70,000 square kilometers of forest were burned in the Amazon region -- this equates to an area the size of Bavaria.

From Science Daily

He planned on throwing a pitch 175 kilometers per hour, or about 109 mph.

From Los Angeles Times

While many cheesemakers told us they felt isolated from potential partners, we found a potential partner was right around the corner – just one or two kilometers in most cases.

From Salon