The Collaborative International Dictionary of English v.0.48:
Dispersion \Dis*per"sion\, n. [CF. F. dispersion.]
1. The act or process of scattering or dispersing, or the
state of being scattered or separated; as, the Jews in
their dispersion retained their rites and ceremonies; a
great dispersion of the human family took place at the
building of Babel.
The days of your slaughter and of your dispersions
are accomplished. --Jer. xxv.
2. (Opt.) The separation of light into its different colored
rays, arising from their different refrangibilities.
Dispersion of the optic axes (Crystallog.), the separation
of the optic axes in biaxial crystals, due to the fact
that the axial angle has different values for the
different colors of the spectrum.