- The definition of an etalon is an instrument that is used to measure the wavelength of light.
An example of etalon is the equipment used to stabilize the wavelength of a laser.
etalon definition by Webster's New World
etalon - Computer Definition
A spectroscopic instrument used to measure and control optical wavelengths. Also known as an interferometer, an etalon comprises two parallel reflecting plane surfaces. Etalons are widely used in lasers. See also Fabry-Perot laser.
In optical networking, an etalon is a passive filter that uses a Fabry-Perot cavity. See Fabry-Perot.