Definition of Snell's law in English:

Snell's law

Pronunciation /ˈsnelz ˌlô/ /ˈsnɛlz ˌlɔ/


  • A law stating that the ratio of the sines of the angles of incidence and refraction of a wave are constant when it passes between two given media.

    • ‘Fermat proposed that light follows the path which takes the shortest time, enabling Snell's law of refraction to be deduced mathematically.’
    • ‘In bi-directional transmission distribution functions it is also necessary to include refraction, which is described by Snell's law.’
    • ‘The largest angle allowed in the photoresist film is inversely related to its refractive index, as calculated using Snell's law and assuming a 90° half angle in air.’
    • ‘One might imagine that an experimental determination of Snell's law would be a simple matter.’
    • ‘This was developed with ray diagrams and key formulae such as Snell's law and the lens equation.’


Late 19th century named after Willebrord van Roijen Snell (1591–1626), Dutch mathematician.


Snell's law

/ˈsnelz ˌlô/ /ˈsnɛlz ˌlɔ/