out·​break | \ˈau̇t-ˌbrāk \

Definition of outbreak 

1a : a sudden or violent increase in activity or currency the outbreak of war

b : a sudden rise in the incidence of a disease an outbreak of measles

c : a sudden increase in numbers of a harmful organism and especially an insect within a particular area an outbreak of locusts

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Examples of outbreak in a Sentence

there was an immediate outbreak of paper shuffling and a pretense of work when the supervisor passed through the room the government quelled the outbreak with ruthless efficiency

Recent Examples on the Web

The earliest reported symptoms in this outbreak began on May 14 and those who are ill range in age from 13 to 79 years old. Matthew Diebel, USA TODAY, "More than 200 hit by parasite from Del Monte vegetables; symptoms can include 'explosive' bowel movements," 9 July 2018 Justin Sullivan/Getty Images After four months, the biggest E. Coli outbreak in more than a decade is finally over. Julia Belluz, Vox, "The romaine lettuce E. Coli outbreak is finally over," 29 June 2018 The World Health Organisation said that the Ebola outbreak in the Democratic Republic of Congo has largely been contained, but officials warned against complacency. The Economist, "Politics this week," 21 June 2018 The outbreak began in March 2013, and wouldn’t be declared over by the Centers of Disease Control until July 2014. Jason Duaine Hahn, PEOPLE.com, "Family Wins $1.9 Million Lawsuit After Salmonella Infected From Chicken Almost Kills Toddler," 15 June 2018 The outbreak in San Diego is so serious, the city is sanitizing streets. Justin L. Mack, Indianapolis Star, "What you need to know: Indiana Burger King worker with Hepatitis A handled food while sick," 6 June 2018 The department cautioned that the gonorrhea outbreak is ongoing, in line with a national trend of increasing rates of STDs. Tegan Hanlon, Anchorage Daily News, "‘Kind of alarming’: Number of new gonorrhea cases in Alaska skyrockets in 2017," 29 May 2018 The first case of Ebola appeared in Mbandaka last Thursday, about a week and a half after the outbreak began in the rural parts of the DRC. Adam K. Raymond, Daily Intelligencer, "Ebola Patients Escape Hospital, Increasing Fear of Massive Outbreak," 24 May 2018 The International Federation of Red Cross and Red Crescent Societies in Congo warned that the outbreak is far from over. Time, "Congo Confirms Six New Ebola Virus Cases as Vaccination Efforts Get Underway," 23 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'outbreak.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of outbreak

1562, in the meaning defined at sense 1a

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Statistics for outbreak

Last Updated

8 Dec 2018

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Time Traveler for outbreak

The first known use of outbreak was in 1562

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More Definitions for outbreak



English Language Learners Definition of outbreak

: a sudden start or increase of fighting or disease


out·​break | \ˈau̇t-ˌbrāk \

Kids Definition of outbreak

: a sudden occurrence or increase of something an outbreak of chicken pox


out·​break | \ˈau̇t-ˌbrāk \

Medical Definition of outbreak 

1 : a sudden rise in the incidence of a disease an outbreak of measles

2 : a sudden increase in numbers of a harmful organism and especially an insect within a particular area an outbreak of locusts

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More from Merriam-Webster on outbreak

Rhyming Dictionary: Words that rhyme with outbreak

Thesaurus: All synonyms and antonyms for outbreak

Spanish Central: Translation of outbreak

Nglish: Translation of outbreak for Spanish Speakers

Britannica English: Translation of outbreak for Arabic Speakers

Comments on outbreak

What made you want to look up outbreak? Please tell us where you read or heard it (including the quote, if possible).


to make faulty or ineffective

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