phrase the angle that a beam of light or other energy that is reflected from a surface makes with a line vertical to that surface: 反射角 This is only visible at certain angles of reflection. The angle of incidence is equal to the angle of reflection. In this equation, 'R' stands for the angle of reflection. The laser's angle of reflection is 30 degrees. The angle of reflection refers to the angle of the reflected ray travelling away from the surface and the perpendicular to the surface. See also