I. āˈshel noun
( -s )
Etymology: French échelle ladder
: a lacing of ribbons on the stomacher of a 17th century costume
II. noun
( -s )
Etymology: French échelle ladder, from Old French eschiele, from Late Latin scala — more at scale
: a diffraction grating made by ruling narrow flat steps on a plane metallic mirror and having a grating space and resolving power intermediate between an echelette and an echelon