- a device used in spectroscopy to measure wavelengths by interference effects produced by multiple reflections between parallel half-silvered glass or quartz plates
WordReference Random House Unabridged Dictionary of American English © 2026
e•ta•lon
(āt′l on′),USA pronunciation n. [Optics.]
- Opticsan interferometer consisting of two glass plates that reflect approximately half of each ray of light incident upon them and that are separated by a small, fixed distance: used to compare wavelengths and to study atomic spectra.
- Gmc; see stall1
- French; Middle French estalon standard, derivative of Old French estal place
- 1900–05
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etalon /ˈɛtəˌlɒn/ n