This means that the light leaving the prism is spread out into its different colours, a process called dispersion. This experiment is recorded as first being carried out by Isaac Newton ...

Refraction close refractionProcess by which a wave changes speed and sometimes direction upon entering a denser or less dense medium, eg a light ray changes direction when refracted by a lens.

Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London, Vol. 3 (1830 - 1837), p. 326 (1 page) ...