incidence

noun

in·​ci·​dence ˈin(t)-sə-dən(t)s 

-ˌden(t)s

1

a

: rate of occurrence or influence

a high incidence of crime

b

: an act or the fact or manner of falling upon or affecting : occurrence

2

a

: angle of incidence

b

: the arrival of something (such as a projectile or a ray of light) at a surface

Did you know?

The words incident, incidence, and instance may seem similar (and, in fact, incident and incidence are closely related), but they are applied in different ways. In current use, incidence usually means "rate of occurrence" and is often qualified in some way ("a high incidence of bear sightings"). 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 a simple change bringing real improvement"); it can also be synonymous with case ("many instances/cases in which the wrong form was submitted"). The plural incidences sometimes occurs in such contexts as "several recent incidences of bear sightings," 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

Breast Cancer Rates for AAPI Women Rise Fastest Among the Young The latest research from the American Cancer Society evaluated breast cancer incidence and mortality in women in the United States using data from the National Cancer Institute and the Centers for Disease Control and Prevention (CDC). —Lauryn Higgins, Flow Space, 13 Dec. 2024

However, low-income women have seen increases in cervical cancer rates, and women of color have higher incidence and deaths from the cancer. —Eduardo Cuevas, USA TODAY, 11 Dec. 2024

In 2022, there were 1,292 cases of SFR in the U.S., according to CDC data, and California saw an incidence rate of 0.31 per million people. —Thomas G. Moukawsher, Newsweek, 29 Nov. 2024

Arizona's lung cancer incidence rate had been falling about 5% per year between 2017 and 2021, according to the National Cancer Institute. —Lauren De Young, The Arizona Republic, 26 Nov. 2024

Word History

First Known Use

1626, in the meaning defined at sense 2a

Phrases Containing incidence

• angle of incidence

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Kids Definition

incidence

noun

in·​ci·​dence ˈin(t)-səd-ən(t)s 

-sə-ˌden(t)s

1

: angle of incidence

2

: rate of occurrence

a high incidence of illness

Medical Definition

incidence

noun

in·​ci·​dence ˈin(t)-səd-ən(t)s, -sə-ˌden(t)s 

1

a

: angle of incidence

b

: the arrival of something (as a ray of light) at a surface

2

a

: an act or the fact or manner of occurring or affecting

diseases of domestic incidence

—Science

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