in·​ci·​dence | \ ˈin(t)-sə-dən(t)s How to pronounce incidence (audio) , -ˌden(t)s\

Definition of incidence

b : the arrival of something (such as a projectile or a ray of light) at a surface
2a : an act or the fact or manner of falling upon or affecting : occurrence
b : rate of occurrence or influence a high incidence of crime

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Did You Know?

The words incident, incidence, and instance may seem similar (and, in fact, incident and incidence are closely related), but they are not used identically. In current use, incidence usually means "rate of occurrence" and is often qualified in some way ("a high incidence of diabetes"). Incident usually refers to a particular event, often something unusual or unpleasant ("many such incidents go unreported"). Instance suggests a particular occurrence that is offered as an example ("another instance of bureaucratic bumbling"); it can also be synonymous with case ("many instances in which the wrong form was submitted"). The plural incidences sometimes occurs in such contexts as "several recent incidences of crime," but this use is often criticized as incorrect.

Examples of incidence in a Sentence

an increased incidence of diabetes a high incidence of criminal behavior

Recent Examples on the Web

Contrary to President Trump’s beliefs, tariffs are paid by the importing party, not by exporters, and the incidence of this tax — i.e., the question of who actually ends up paying it — ends up being a very complicated question. Kevin D. Williamson, National Review, "Invest in the Neighborhood," 4 June 2019 Particularly concerning is the increase in the incidence of maternal opioid use. Hayley Krischer, Marie Claire, "How Heroin Came for Middle-Class Moms," 20 Aug. 2018 But the incidences of red tides seem to have increased since the 1950s and 1960s. Kate Furby, The Seattle Times, "Red tide algae’s deadly toll on sea life has triggered a state of emergency in Florida," 14 Aug. 2018 The rate of liver cancer incidence is rising faster than that for any other cancer — a trend the American Cancer Society attributes to the high rate of undiagnosed hepatitis C among baby boomers. Julia Belluz, Vox, "We’re making real progress against cancer. But you may not know it if you’re poor.," 8 Jan. 2019 The ability to watch changes in incidence and prevalence of disease and other public health crises like opioid abuse provides tremendous value to state and local health departments. John Freedman, STAT, "Every state needs a database with all health insurance claims, not just some," 5 June 2018 In contrast, incidence has increased 51 percent since 1994 among adults under 50. Marie Mccullough,, "American Cancer Society urges colon cancer screening starting at 45, not 50," 30 May 2018 The County Health and Human Services Agency’s Behavioral Health Services funded the exhibit, designed to raise awareness about the incidence and impact of suicide among college students. Laura Groch,, "North County School News, May 17," 17 May 2018 Cappos says that incidences where cyber tools developed by the NSA have been leaked and use by hackers underlines the growing threat of talented criminals utilizing cutting-edge technology. Patrick Sisson, Curbed, "As cities get high-tech, hackers become more dangerous," 18 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'incidence.' 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 incidence

1626, in the meaning defined at sense 1a

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Last Updated

16 Jun 2019

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Time Traveler for incidence

The first known use of incidence was in 1626

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English Language Learners Definition of incidence

: the number of times something happens or develops : the rate at which something occurs
technical : the angle at which a ray (such as a ray of light) hits a surface


in·​ci·​dence | \ ˈin(t)-səd-ən(t)s, -sə-ˌden(t)s How to pronounce incidence (audio) \

Medical Definition of incidence

b : the arrival of something (as a ray of light) at a surface
2a : an act or the fact or manner of occurring or affecting diseases of domestic incidenceScience
b : rate of occurrence or influence especially : the rate of occurrence of new cases of a particular disease in a population being studied — compare prevalence

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More from Merriam-Webster on incidence

Spanish Central: Translation of incidence

Nglish: Translation of incidence for Spanish Speakers

Britannica English: Translation of incidence for Arabic Speakers

Comments on incidence

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


incapable of being surmounted or overcome

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