incidence
UK: ˈɪnsɪdəns | US: ˈɪnsɪdəns
n. the rate or frequency of an event, especially something undesirable (e.g., disease, crime)
n. the manner or angle at which something (e.g., light, a surface) meets or strikes another
n. (physics) the arrival of radiation or a projectile at a surface
Derived from Latin incidentia ("a falling upon"), from incidere ("to fall into/upon"), combining in- (upon) + cadere (to fall). The root cid (from cadere) appears in related words like "accident" (unexpected event) and "deciduous" (falling off). Originally describing physical impact (e.g., light falling on a surface), it later generalized to statistical occurrences.
The incidence of diabetes has risen sharply in urban areas.
The angle of incidence affects how light reflects off the mirror.
Scientists measured the incidence of cosmic rays on the satellite.
High crime incidence correlates with economic inequality.
The study tracks the incidence of rare genetic mutations.