The dependence of a wave’s velocity on its frequency. Objects that have this property are called dispersive media, and can separate a beam of light into its various wavelength components, such as a dispersive prism. Another common example of light dispersion is a rainbow.
c.1450, from M.Fr. disperser "scatter," from L. dispersus, pp. of dispergere "to scatter," from dis- "apart, in every direction" + spargere "to scatter."