English dictionary, thesaurus, translations & etymology
FreeDict.com
noun Common

incidence

IHN-sih-duhns

Incidence (noun) means the rate at which something occurs, especially within a given group or period. Example: “The incidence of the disease has fallen since the vaccine was introduced.”

noun
1
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."
2
(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
Common pairings
high incidence incidence of disease angle of incidence

Word Forms

incidences plural

Study it as flashcards or scroll it in Flow — saved to your collection.
Test yourself on “incidence” A quick quiz — meaning, synonyms & usage

Fill the Gap

Can you complete this real example?

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

Etymology

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

Origin: Medieval Latin

Related Words

Rhymes for incidence

See all rhymes for incidence →

Frequently Asked Questions

What does “incidence” mean?

The word “incidence” means the rate at which something occurs, especially within a given group or period. In plain terms, how often something happens, or (in physics) the angle at which something hits a surface.

How do you pronounce “incidence”?

“Incidence” is pronounced IHN-sih-duhns (/ˈɪn.sɪ.dəns/ in IPA).

How do you use “incidence” in a sentence?

Here is “incidence” used in a sentence: “The incidence of the disease has fallen since the vaccine was introduced.”

What part of speech is “incidence”?

“Incidence” is a noun.

Where does the word “incidence” come from?

The word “incidence” comes from Medieval Latin. From Medieval Latin incidentia, "a falling upon," from Latin incidere, "to fall upon" (in- + cadere, "to fall").

Is “incidence” a common word?

“Incidence” is a fairly common word in modern English.

How many meanings does “incidence” have?

“Incidence” has 2 distinct senses listed in this dictionary. The most common is: the rate at which something occurs, especially within a given group or period.

What is the difference between incidence and incidents?

Incidence refers to the rate at which something occurs within a group or period, such as 'the incidence of the disease increased,' while incidents are individual events or occurrences themselves. Confusing the two is a common mistake because they sound similar but incidence is not simply the plural of incident.

What is the difference between incidence and prevalence?

Incidence measures the rate of new occurrences of something within a given period, while prevalence measures the total number of existing cases at a given time, regardless of when they started. Both are used to describe how common something is, but they capture different aspects.

What does angle of incidence mean in physics?

In physics, the angle of incidence describes the way a ray of light or a projectile strikes a surface, measured from a line perpendicular to that surface. It is a key concept in explaining reflection and refraction.

Featured In

People Also Searched

Definitions: FreeDict original editorial