say it: ESH-uh-lahn
echelon is a noun meaning "status in a society or organization". It carries 3 recorded senses.
a diffraction grating consisting of a pile of plates of equal thickness arranged stepwise with a constant offset
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for echelon come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.