Define dispersion of light?

Dear Student,

Dispersion:The phenomenon of splitting up of white light into its constituent colours is known as dispersion. 

For example,

When light passes through one face of a prism it gets deviated.

 This deviation is different for different wavelengths of light. Since different colors of light have different wavelength, the deviation for different color is different. As a result, when the light emerges from the other face of the prism we observe the 

seven constituent of light.This phenomenon of splitting of light into its constituent colors is called dispersion.

Regards