Huygens principle

noun 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.

Origin of Huygens principle

First recorded in 1830–40; named after C. Huygens
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018