Polarization is the property of waves that allows them to oscillate in more than one direction. The polarization of light is described by the position of the wave’s electric field at a point in space over the time of one oscillation. Polarization is perpendicular to the wave’s direction of travel. The electric field may be positioned in a single direction or it may rotate as the wave travels.
Many sources of electromagnetic radiation have many molecules that will emit light. Light is only polarized if there is a relationship between the emitters of light. Light can be described by the degree of polarization. It may also be described by the conditions of the polarization ellipse.