outbreak
Americannoun
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a sudden breaking out or occurrence, especially of something bad or unpleasant; eruption.
the outbreak of war.
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a sudden and active manifestation.
an outbreak of hives.
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a sudden increase in the incidence of a disease or medical condition in a particular place or population: a worldwide polio outbreak in the early 1900s.
a serious outbreak of malaria in northern Uganda;
a worldwide polio outbreak in the early 1900s.
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an outburst.
an outbreak of temper.
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an insurrection, revolt, or mutiny.
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a public disturbance; riot.
noun
Etymology
Origin of outbreak
Explanation
A sudden or abrupt onset of something really bad is an outbreak. You could experience an outbreak of measles or an outbreak of violence; either way, try to protect yourself. When you talk about an outbreak of something, it's almost always something terrible, or at least unwanted. You might hear about an outbreak of war in a distant country, or an outbreak of violence in a big city, or an outbreak of disease among farm animals. Outbreak started as a Middle English verb around 1300, becoming a noun meaning "eruption" about three hundred years later.
Vocabulary lists containing outbreak
The Boy in the Striped Pajamas
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Talk Like Shakespeare Day, List 6
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“Vaccine Controversy Shows Why We Need Markets, Not Mandates” by Ron Paul
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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 outbreak, which experts suspect was circulating under the radar for some time, is caused by the less common Bundibugyo strain, for which there are no approved vaccines or treatments.
From Barron's • May 23, 2026
But the outbreak of World War I forced him to return to Germany, where he opened his first art school in Munich.
From The Wall Street Journal • May 23, 2026
The World Health Organization has declared the outbreak of the highly contagious haemorrhagic fever an international emergency.
From Barron's • May 23, 2026
"The challenge is the operational environment, including insecurity, displacement, limited infrastructure and intense population movement, which make outbreak control far more complex."
From BBC • May 22, 2026
Adams instructed his beloved Abigail to start saving all his letters even before the outbreak of the war for independence.
From "Founding Brothers: The Revolutionary Generation" by Joseph J. Ellis
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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.