red alert
Americannoun
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(in military or civilian defense) the most urgent form of alert, signaling that an enemy attack is believed to be imminent.
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the signal or alarm sounded for this alert.
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a signal or warning that a critical situation is developing or has occurred.
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the period during which a state of crisis or danger is declared to exist.
Etymology
Origin of red alert
First recorded in 1960–65
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.
In its latest heatwave bulletin published on Saturday, the Italian health ministry says that by Monday, some 25 of the country's 27 major cities will be on red alert.
From BBC ● Aug. 1, 2026
The app, having activated the red alert, suggests a healthier alternative.
From BBC ● Jul. 13, 2026
Scientists said in a study released Friday that climate change was "unequivocally" responsible for the heat that broke records in Britain, France, Spain and Switzerland, while the Netherlands issued its first-ever red alert over heat.
From Barron's ● Jun. 26, 2026
As temperatures were expected to ease in western Europe from Friday, eastern Europe was on red alert, with the mercury set to climb.
From Barron's ● Jun. 26, 2026
"The Bionic Unit is on red alert," he says.
From "Freak The Mighty" by Rodman Philbrick
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.
