Fermat's principle

noun

: a statement in optics: the path actually followed by a ray of light undergoing reflection or refraction is one of either minimum or maximum time as compared with adjacent arbitrary paths except for reflection or refraction at an aplanatic surface or passage through an aplanatic lens for which the time is constant

Word History

Etymology

after Pierre de Fermat †1665 French mathematician, its formulator

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

Dictionary Entries Near Fermat's principle

Cite this Entry

“Fermat's principle.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Fermat%27s%20principle. Accessed 31 Oct. 2024.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!