angle of incidence

WordReference Random House Unabridged Dictionary of American English © 2026

an′gle of in′cidence, 

1. Optics, Physics, Optics Also called incidence. the angle that a straight line, ray of light, etc., meeting a surface, makes with a normal to the surface at the point of meeting.
2. Aeronautics (on an airplane) the angle, usually fixed, between a wing or tail root chord and the axis of the fuselage.
3. [Chiefly Brit.] See angle of attack (def. 1).
• 1620–30

Collins Concise English Dictionary © HarperCollins Publishers::

angle of incidence noun

1. the angle that a line or beam of radiation makes with the normal to the surface at the point of incidence
2. Also called: rigging angle of incidence the angle between the chord line of an aircraft wing or tailplane and the aircraft's longitudinal axis

WordReference Random House Unabridged Dictionary of American English © 2026

an′gle of attack′, 

1. Aeronautics Also called,[esp. Brit.,] angle of incidence. the acute angle between the chord of an aircraft wing or other airfoil and the direction of the relative wind.
2. Rail Transport the angular attitude of a wheel flange to the rail, esp. on curves.
• 1905–10