heat wave
Americannoun
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a period of abnormally hot and usually humid weather; heat event.
I moved to the coast up north because summer back home has become one long, unbearable heat wave.
-
an air mass of high temperature covering an extended area and moving relatively slowly.
Another heat wave is expected to form across the South and into the Northeast by week’s end.
noun
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a continuous spell of abnormally hot weather
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(not in technical use) an extensive slow-moving air mass at a relatively high temperature
Other Word Forms
Noun Inflected Forms
Etymology
Origin of heat wave
First recorded in 1875–80
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.
The marine heat wave isn’t even being influenced by El Niño at this time; El Niño’s effects will only begin to be seen in coastal ocean temperatures starting in the fall.
From Los Angeles Times ● Jul. 20, 2026
The retailer Carrefour sold 30,000 AC units in a day amid a heat wave last month—”a thousand times more than on a normal day,” CEO Alexandre Bompard told the Agence France-Presse.
From The Wall Street Journal ● Jul. 19, 2026
For example, during a dangerous heat wave in early July, air conditioning in one section of the facility also went down.
From Salon ● Jul. 17, 2026
Since then the complaints, and violations, have continued to stack up, just as a summer heat wave settled over the region.
From Los Angeles Times ● Jul. 17, 2026
“Ye need help?” he said, his strangely accented Russian reaching her ears on a heat wave that smelled of fire and metal.
From Anya and the Dragon by Sofiya Pasternack
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.
