echelette

[ esh-uh-let, ey-shuh- ]
/ ˌɛʃ əˈlɛt, ˌeɪ ʃə- /

noun Spectography.

a diffraction grating designed to reflect infrared radiation.

Origin of echelette

< French échelette rack, equivalent to échelle ladder (see echelon) + -ette -ette
Also called echelette grating.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019