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:
Still, Macquarie notes that recent operating data show limited overall improvement in the trajectory of revenue per average seat kilometer, a key industry metric.
From The Wall Street Journal ● Jul. 1, 2026
"We found that the abundance of grassland birds was more than 70 percent lower at sites next to shelterbelts compared with open sites located about one kilometer away," said Hisano.
From Science Daily ● Jun. 22, 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
On the drone’s video feed, he spotted three Russian soldiers only a kilometer away.
From The Wall Street Journal ● Feb. 9, 2026
There were others, I knew, who would never make it a kilometer.
From "Prisoner B-3087" by Alan Gratz
An evacuation zone extending 100 kilometers beyond Yellowstone National Park is announced, affecting roughly 200,000 residents, as well as thousands of visitors in the region.
From Science Daily ● Sep. 22, 2026
Expanding gases and intense heat drive this material upwards, creating a vast eruption column rising 30–50 kilometers into the atmosphere – far above commercial passenger aircraft, which usually cruise at up to about 13 kilometers.
From Science Daily ● Sep. 22, 2026
“Protecting hundreds of kilometers of energy infrastructure remains challenging, suggesting that durable regional de-escalation and security arrangements ultimately provide a more effective solution than additional infrastructure alone,” they say.
From The Wall Street Journal ● Sep. 18, 2026
Starship is set to fly at an altitude of about 275 kilometers above Earth and complete six orbits around the planet.
From MarketWatch ● Sep. 15, 2026
They took him immediately to Thysville, which is about a hundred kilometers south of Léopoldville over the best road in this nation, repaved recently with a grant of foreign aid.
From "The Poisonwood Bible" by Barbara Kingsolver
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.
