n (General Physics) the angle between the direction of the refracted ray and the direction of the incident ray when a ray of light passes from one medium to another
angle of deviation
an·gle of de·vi·a·tion
1. in a prism, the sum of the angles of incidence and emergence minus the apical angle of a prism; 2. in optics, angle of refraction; 3. in strabismus, angle of anomaly.