Deviation from a prescribed flight path; specifically, circular dispersion especially as applied to missiles.

The frequency dependence of the retardation of radio waves (such as those emitted by a pulsar) when they pass through an ionized gas.

A distribution of finely divided particles in a medium.

The entropy of the output of a communications channel when the input is known.

Scattering of microwave radiation by an obstruction.

In optical mineralogy, the constant optical values at different positions on the spectrum.

1. The separation of a complex of electromagnetic or sound waves into its various frequency components.

2. Quantitatively, the rate of change of refractive index with wavelength or frequency at a given wavelength or frequency.

3. The rate of change of deviation with wavelength or frequency.

4. In general, any process separating radiation into components having different frequencies, energies, velocities, or other characteristics, such as the sorting of electrons according to velocity in a magnetic field.

The degree of spread shown by observations in a sample or a population.