heat wave
Americannoun
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heat waves
plural
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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.
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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.
Temperatures in the ocean around Southern California are higher due to a longstanding and unusual marine heat wave but are generally in the high 60s or low 70s.
From Los Angeles Times ● Sep. 1, 2026
The summer also doubled the previous record number of days above 34 degrees Celsius, or 93 Fahrenheit—14 versus seven in 1976, the year of a notorious heat wave.
From The Wall Street Journal ● Aug. 31, 2026
Amid the heat wave, thousands of Southland residents were sporadically without power as outages popped up in different communities.
From Los Angeles Times ● Aug. 27, 2026
Over in San Francisco, which faced down a severe heat wave in March, Google Weather users were left flummoxed by the charts of low-70s temps, way milder than the 90-degree record felt by downtown residents.
From Slate ● Aug. 21, 2026
On July 20, in the midst of an enervating heat wave in Austria, he traveled from Brno to Vienna to take the oral part of the exam.
From "The Gene" by Siddhartha Mukherjee
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.
