The beam angle is used to describe the directional characteristic of illuminants/lamps. The directivity means the angle-dependent luminous intensity (which is measured in candela). It is used to assess the illumination of surfaces on the one hand or the glare effect of the light source on the other.
The beam angle indicates in which angle the light is emitted to the front (mostly down to the floor). Mostly the illuminant/luminaire hangs from a ceiling and illuminates a room. Light sources such as LED or halogen spots are available with beam angles of 8° - 120°.