incidence Meaning, Definition & Usage

  1. noun the relative frequency of occurrence of something
    relative incidence.
  2. noun the striking of a light beam on a surface
    • he measured the angle of incidence of the reflected light

WordNet

In"ci*dence noun
Etymology
Cf. F. incidence.
Definitions
  1. A falling on or upon; an incident; an event. Obs. Bp. Hall.
  2. (Physics) The direction in which a body, or a ray of light or heat, falls on any surface.
    In equal incidences there is a considerable inequality of refractions. Sir I. Newton.

Webster 1913