A phenomenon whereby the optical properties of a medium vary according to the wavelength of light passing through the medium. When light enters a lens or prism, the dispersion characteristics of the lens or prism cause the index of refraction to vary depending on the wavelength thus dispersing the light. This is also sometimes referred to as color dispersion.canonglossaryeu
The property of materialswhich have a refractive index that varies according to the wavelength of light, i.e.,bend the rays of some colors more than others; a prism placed in the path of a rayof white light bends the blue and violet rays more than the orange and red, so thatit spreads out or disperses the colors as a continuous spectrum.
A phenomenon in which white light rays deviate by different wavelength amounts resulting in a spectrum. The rainbow created by a prism is the result of dispersion.