Meaning of Huygens principle

Huy'gens prin"ciple

Pronunciation: [key]
— Optics, Physics. Optics,Physics.
  1. the principle that all points on a wave front of light are sources of secondary waves and that surfaces tangential to these waves define the position of the wave front at any point in time.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.