noun

incidence

IHN-sih-duhns

noun

The rate at which something occurs, especially within a given group or period.

"The incidence of the disease has fallen since the vaccine was introduced."

(physics) The way a ray of light or a projectile strikes a surface.

"The angle of incidence equals the angle of reflection."

How to Use Incidence

Learner’s notes

In plain EnglishHow often something happens, or (in physics) the angle at which something hits a surface.

Common mistake

Don't confuse with incident (a single event) — incidence is a rate or frequency, not an occurrence itself.

Easily confused with

incident →

Common pairings

high incidence incidence of disease angle of incidence

incidences plural

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The _____ of the disease has fallen since the vaccine was introduced.

From Medieval Latin incidentia, "a falling upon," from Latin incidere, "to fall upon" (in- + cadere, "to fall").

hence fence Pence whence thence Spence absence science silence defence essence Terence