[1] : The Collaborative International Dictionary of English v.0.48

incidence \in"cidence\, n. cf. f. incidence.
   1913 webster
   1. a falling on or upon; an incident; an event; an
      occurrence. obs. --bp. hall.
      1913 webster

   2. physics the direction in which a body, or a ray of light
      or heat, falls on any surface.
      1913 webster

            in equal incidences there is a considerable
            inequality of refractions.            --sir i.
                                                  newton.
      1913 webster

   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.
      pjc

   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.
      1913 webster
see also:
angle of incidence line of incidence 

[2] : The Collaborative International Dictionary of English v.0.48

angle of incidence \angle of incidence\ a"eronautics
   the angle between the chord of an a"erocurve and the
   relative direction of the undisturbed air current.
   webster 1913 suppl.

[3] : WordNet (r) 2.0

angle of incidence
     n : the angle that a line makes with a line perpendicular to the
         surface at the point of incidence syn: incidence angle
see also:
incidence angle 

Angle >> A Words
Angle, definition of term: Angle
angle_pag1.html

Angle Bracket >> A Words
Angle Bracket, definition of term: Angle Bracket
angle+bracket_pag1.html

Angle Iron >> A Words
Angle Iron, definition of term: Angle Iron
angle+iron_pag1.html

Acute Angle >> A Words
Acute Angle, definition of term: Acute Angle
acute+angle_pag1.html

Dihedral Angle >> D Words
Dihedral Angle, definition of term: Dihedral Angle
dihedral+angle_pag1.html

Angle Of Attack >> A Words
Angle Of Attack, definition of term: Angle Of Attack
angle+of+attack_pag1.html

Angle Of Repose >> A Words
Angle Of Repose, definition of term: Angle Of Repose
angle+of+repose_pag1.html