. The characteristic of how light propagates through a waveguide that can be designated by a radiation pattern in a plane transverse to the direction of travel. 2
. The state of an oscillating system such as a laser that corresponds to both a particular field pattern the system generates as well as one of the possible resonant frequencies of the system. In a laser system, the field pattern produced as described above is referred to as a transverse mode and takes the common name(s) Gaussian, Hermite Gaussian, Laguerre-gauss etc. depending on the transverse mode. The resonant frequencies described refer to a longitudinal mode which is the light wavelength at which the laser is designed to operate.