etalon

noun

eta·​lon

ˈātᵊlˌän,

ˈet-

plural -s

: an interferometer in which two parallel partially silvered glass plates at a fixed distance apart produce by multiple reflection interference spectra of high dispersion and resolution adapted to the fine-structure analysis of spectrum lines

Word History

Etymology

French étalon standard of weights and measures, from Middle French estalon, estelon, probably of Germanic origin; akin to Frisian stal shape, form

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now