incidence

/ˈɪnsəd(ə)ns/

/ˈɪnsɪdɪns/

Other forms: incidences

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.

Definitions of incidence

1. noun

   the relative frequency of occurrence of something
   synonyms: relative incidence

   types:

   morbidity

   the relative incidence of a particular disease

   type of:

   frequency, relative frequency

   the ratio of the number of observations in a statistical category to the total number of observations
2. noun

   the striking of a light beam on a surface
   “he measured the angle of incidence of the reflected light”

   type of:

   optical phenomenon

   a physical phenomenon related to or involving light