incidence

American  

[in-si-duhns] / ˈɪn sɪ dəns /

noun

• incidences
  plural

1. the rate or range of occurrence or influence of something, especially of something unwanted.

   the high incidence of heart disease in men over 40.

2. a falling upon, affecting, or befalling; occurrence.

   The incidence of murder that Sunday afternoon shocked the sleepy village.

3. Optics, Physics.

   1. the striking of a ray of light, beam of electrons, etc., on a surface, or the direction of striking.

   2. angle of incidence.

4. the fact or the manner of being incident.

5. Geometry. partial coincidence of two figures, as of a line and a plane containing it.

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incidence British  

/ ˈɪnsɪdəns /

noun

1. degree, extent, or frequency of occurrence; amount

   a high incidence of death from pneumonia

2. the act or manner of impinging on or affecting by proximity or influence

3. physics the arrival of a beam of light or particles at a surface See also angle of incidence

4. geometry the partial coincidence of two configurations, such as a point that lies on a circle

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Other Word Forms

Noun Inflected Forms

• incidences
  plural

Etymology

Origin of incidence

First recorded in 1375–1425; late Middle English, from Late Latin incidentia. See incident, -ence

Explanation

Incidence means the frequency with which something bad occurs. You’ll hear of “incidences of cancer” or “incidences of war." You hope the incidence is decreasing, not increasing. You might confuse incidence and incident. They sound similar, but incident refers only to something that happened, not to the frequency with which it happens. After a car accident, the police file an incident report, which is a fancy way of saying they write down what happened. Looking at these reports grouped together can show you if the incidence of accidents at specific intersections in town is on the rise.

Example Sentences

See Examples For:

incidence incidences

The Centers for Disease Control and Prevention reported Thursday that there were 2,371 confirmed measles cases nationwide this year, marking the highest incidence of cases since 1991.

From Los Angeles Times ● Aug. 2, 2026

The incidence of dengue has increased 30-fold over the last 50 years, according to the World Health Organisation, which categorises the disease among the top ten global health threats.

From BBC ● Jul. 23, 2026

Since 2011, incidence of most food-borne illness has remained flat.

From The Wall Street Journal ● Jul. 22, 2026

Earlier technologies typically required light to hit the material at very steep angles to achieve similar effects, reducing both absorption and radiation efficiency compared with normal incidence.

From Science Daily ● Jul. 7, 2026

By 1950 the incidence of Dutch elm disease in New York City had been reduced to %o of 1 per cent of the city’s 55,000 elms.

From "Silent Spring" by Rachel Carson

Local rail has also seen a rise in incidences, such as delays, cancellations and technical problems, which have more than tripled since 2019 on the Madrid local Cercanías network.

From BBC ● Jan. 23, 2026

One example featured a patient hospitalized for gout who told viewers that they "can reduce your incidences of gout if you cut back on your salt, your alcohol, and your red meat."

From Science Daily ● Jan. 9, 2026

"Previous to these incidences, I wouldn't have described him as an angry child," he said.

From BBC ● Jul. 2, 2025

In recent months, several major retailers have scaled back on self-checkout machines, citing customer feedback, increased shoplifting incidences and profit losses as key factors in their decisions.

From Salon ● Jul. 17, 2024

While these new incidences of yellow fever were few and scattered, they demonstrated clearly that the disease had not been completely wiped out.

From "An American Plague: The True and Terrifying Story of the Yellow Fever Epidemic of 1793" by Jim Murphy

Related Words

• extent
• frequency
• percentage
• prevalence
• proportion
• rate