01 n. A falling on or upon; an incident; an event; an occurrence.
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1.
A falling on or upon; an incident; an event; an occurrence.[Obs.]
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2.
The direction in which a body, or a ray of light or heat, falls on any surface.(Physics)“In equal incidences there is a considerable inequality of refractions.” — Sir I. Newton.
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3.
The rate or ratio at which something occurs; as, the incidence of murder in Los Angeles; the incidence of cancer in men over 50.
Phrases & compounds
Angle of incidence —
the angle which a ray of light, or the line of incidence of a body, falling on any surface, makes with a perpendicular to that surface; also formerly, the complement of this angle.
Line of incidence —
the line in the direction of which a surface is struck by a body, ray of light, and the like.