Origin: Latin suffix -ence
Incidence has 3 different meanings across 1 category:
the relative frequency of occurrence of something
"The incidence of flu cases in the northern region was significantly higher than in the south during winter months."
the striking of a light beam on a surface
"he measured the angle of incidence of the reflected light"
The act of something happening; occurrence.
"The incidence of rare diseases in that region has increased significantly over the last decade."
In plain English: Incidence is how often something happens within a specific group of people over time.
"The incidence of heart disease has increased in recent years due to an aging population."
Usage: Use incidence to describe how often an event occurs within a specific group or area, rather than the general fact that it happened once. It is frequently confused with incident, which refers to a single specific event instead of its frequency.
The word "incidence" comes from the Old French incidentie, which was borrowed from Medieval Latin to mean "a falling upon." It entered English with this original sense, describing something that happens or falls on a specific subject.