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
That all spells exciting times for sleepy, regulated natural monopolies that control the last kilometer to the customer.
From Barron's ● May 27, 2026
But it’s benefiting from an acceleration in growth of revenue per average seat kilometer in 2H, albeit on lower capacity.
From The Wall Street Journal ● Apr. 15, 2026
To identify detailed pollution patterns, the team divided the continental United States into a grid made up of 4 kilometer by 4 kilometer squares.
From Science Daily ● Jan. 26, 2026
After half a kilometer or so, Helena slid from my nearly numb arms to the ground in front of the Zielinskis’ gate.
From "The Light in Hidden Places" by Sharon Cameron
These surge for tens of kilometers, splintering trees, igniting forests and burying the remnants beneath hot ash and pumice.
From Science Daily ● Sep. 22, 2026
The laboratory sits beneath 1.4 kilometers of radiation-dampening rock, which blocks much of the background interference that would otherwise complicate the search.
From Science Daily ● Sep. 21, 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
“My school is about five kilometers that way.”
From "Darius the Great Is Not Okay" by Adib Khorram
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.
