kilometer
Americannoun
-
kilometers
plural
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
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of kilometer
First recorded in 1800–10; from French kilomètre; see origin at kilo-, meter 1
Explanation
A kilometer is a unit of metric measurement that's about 2/3 as long as a mile. If you sign up for a five kilometer race, you'll be running a course that's a little over three miles long. Most countries around the world measure geographical distance using kilometers rather than miles — the exceptions are the U.S. and the U.K. The word means "one thousand meters," from Greek roots khilioi, "thousand," and metron, "measure." As you might guess, there are a thousand meters in a single kilometer. If you drive from the U.S. across the Canadian border, expect to see speed limit signs change from miles per hour to kilometers per hour.
Vocabulary lists containing kilometer
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
The 82-year-old is the brains behind the IceCube Neutrino Observatory, a telescope embedded in a cubic kilometer of Antarctic ice that detects neutrinos -- particles with almost no mass that seldom interact with other matter.
From Barron's ● Oct. 6, 2026
That all spells exciting times for sleepy, regulated natural monopolies that control the last kilometer to the customer.
From Barron's ● May 27, 2026
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 ● Feb. 21, 2026
On the drone’s video feed, he spotted three Russian soldiers only a kilometer away.
From The Wall Street Journal ● Feb. 9, 2026
“It’s only a kilometer from here,” he said.
From "The Kite Runner" by Khaled Hosseini
In the northern Finnish town of Muhos, 36-year-old farmer Joni Pitkanen is preparing for life with a new neighbour -- just kilometers away, tech giant Google is planning to build new data centres.
From Barron's ● Oct. 4, 2026
Now in its initial orbital mission, Starship is expected to fly at an altitude about 275 kilometers above Earth and complete as many as six orbits around the planet over the course of several hours.
From The Wall Street Journal ● Sep. 28, 2026
In taking the coastal areas around Bab el-Mandeb village, they reap the benefit of Emirati investment, manifested in kilometers of paved highways that stand in stark contrast to much of Yemen’s road network.
From Los Angeles Times ● Sep. 27, 2026
From there, however, people would still have had to move it hundreds of kilometers to Salisbury Plain.
From Science Daily ● Sep. 23, 2026
Uncle Abdullah spoke with them, and I learned that they were walking the 147 kilometers to Makeni in order to escape the debils.
From "Taking Flight: From War Orphan to Star Ballerina" by Michaela DePrince
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
