General polarization: Some waves can be described by having the electric field perpendicular to the direction of the wave, and these are called TE (transverse electric) waves. Others have the magnetic field perpendicular to the direction of the wave, and these are called TM (transverse magnetic) waves. These are the most general types of wave polarization. They can also be called vertical or horizontal polarized waves. If both the electric field and magnetic field are perpendicular to the direction of the wave, the wave is called TEM (transverse electromagnetic). Linear, circular, and elliptical polarizations are specific cases of TEM polarization.