Polarization (Brit. polarisation) is a property of transverse waves which escribes the orientation of the oscillations in the plane perpendicular to the wave's direction of travel. This concept is used in areas of science and technology dealing with wave propagation, such as optics, seismology, and telecommunications. In electrodynamics, polarization characterizes electromagnetic waves, such as light, by specifying the direction of the wave's electric field. Longitudinal waves such as sound waves in liquids and gases do not exhibit polarization, because for these waves the direction of oscillation is along (and thus is uniquely determined by) the direction of wave's travel. In contrast, the direction of the (electric field) oscillation in electromagnetic waves is not uniquely determined by the direction of propagation. Similarly, the direction of shear stress in a transverse sound wave in a solid can have any orientation in the plane that is perpendicular to the propagation direction. The term polarization thus describes the possible orientations of the oscillatory process in the plane perpendicular to the transverse wave's path.