Dispersion

Dispersion can mean any of several things:

• A phenomenon that causes the separation of a wave into components of varying frequency. See dispersion (optics) and dispersion (water waves).
• In chemistry:
  • A stable or unstable system of fine particles, larger than colloidal size, evenly distributed in a medium.
  • The fraction of atoms of a material exposed to the surface. See dispersion (materials science).
• In the technical terminology of gemology, the difference in the refractive index of a material at the B and G Fraunhofer wavelengths of 686.7 nm and 430.8 nm. Simply, the degree to which the gemstone shows fire or color. See Abbe number and dispersion (optics).
• Statistical dispersion.