kilometer

American  

[ki-lom-i-ter, kil-uh-mee‑] / kɪˈlɒm ɪ tər, ˈkɪl əˌmi‑ /

especially British, kilometre

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

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kilometer Scientific  

/ 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

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kilometer Cultural  

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

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Pronunciation

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

Etymology

Origin of kilometer

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

Example Sentences

Evidence of accelerated aging and increased breakdown of red blood cells was visible after the 40 kilometer race and was even more pronounced among athletes who completed the 171 kilometer event.

From Science Daily

The Galapagos Islands, a World Heritage Site, are situated some 1,000 kilometers off the coast of Ecuador.

From Barron's

The boxes can be more than 100 kilometers across.

From The Wall Street Journal

Their analysis shows that roughly 300 million cubic meters of magma rose from deep within the crust and stalled about four kilometers beneath the seafloor.

From Science Daily

Orlando Palomino, a 44-year-old who pedals up to 70 kilometers a day as he ferries people from town to town, boasted that he had work "from Monday to Monday."

From Barron's