kilometer

especially British, kil·o·me·tre

[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

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 has been used since the early 1800's. A second pronunciation: , 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 Word Forms

• kilometric adjective
• kilometrical adjective

Word History and Origins

Origin of kilometer¹

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

Example Sentences

“Plus, I have a yard in the back of my house that’s a kilometer long where I run.”

From Los Angeles Times

Additionally, mining operations scrape up the seafloor, producing sediment plumes that can disrupt an area up to hundreds of kilometers away from the operating site, Mullineaux said.

From Salon

“But we said, ‘OK, you’ll walk without walking sticks or without crutches one kilometer.’

From Los Angeles Times

In much the same way, the Russian state has convinced its vatniks to fight and die for oligarchs who wouldn’t let them within five kilometers of their palaces.

From Salon

He threw a fastball that was registered at 163 kilometers per hour — or about 101 mph.

From Los Angeles Times