. (Aëronautics) The angle between the chord of an aërocurve and the relative direction of the undisturbed air current. [ Webster 1913 Suppl. ]

n. [ Cf. F. coïncidence. ] 1. The condition of occupying the same place in space; as, the coincidence of circles, surfaces, etc. Bentley. [ 1913 Webster ]

2. The condition or fact of happening at the same time; as, the coincidence of the deaths of John Adams and Thomas Jefferson. [ 1913 Webster ]

3. Exact correspondence in nature, character, result, circumstances, etc.; concurrence; agreement. [ 1913 Webster ]

The very concurrence and coincidence of so many evidences . . . carries a great weight. Sir M. Hale. [ 1913 Webster ]

Those who discourse . . . of the nature of truth . . . affirm a perfect coincidence between truth and goodness. South. [ 1913 Webster ]

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 ]

n. The quality of being incoincident; lack of coincidence. [ R. ] [ 1913 Webster ]

n. Lack of coincidence. [ 1913 Webster ]