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

Black women, similarly, experience a 38% higher mortality rate despite a 5% lower incidence. —Sarah Scott, Verywell Health, 28 Oct. 2024

The pharmaceutical giant was transparent about the risks, providing detailed information to the public and healthcare providers about the incidence of blood clots and the steps to address the issue. —Vanessa Tan, Forbes, 21 Oct. 2024

Socioeconomic status and education level, which vary widely between Asian Indians and Pacific Islanders or Southeast Asians, could explain these disparities in breast cancer incidence and mortality, Chew said. —Claire Wang, NBC News, 20 Oct. 2024

Young Asian American and Pacific Islander women saw the greatest annual increase in breast cancer incidence compared with any other demographic, at 2.5 percent. —Shi En Kim, Smithsonian Magazine, 3 Oct. 2024

Word History

First Known Use

1626, in the meaning defined at sense 2a

Phrases Containing incidence

• angle of incidence

Podcast

Get Word of the Day delivered to your inbox!

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