Fermat's principle


noun

Optics. the law that the path taken by a ray of light in going from one point to another point will be the path that requires the least time.

Origin of Fermat's principle

First recorded in 1885–90; named after P. de Fermat

British Dictionary definitions for fermat's principle

Fermat's principle

noun

physics the principle that a ray of light passes from one point to another in such a way that the time taken is a minimum