(chemistry) Initialism of epichlorohydrin.

(military, US) Initialism of Enhanced Combat Helmet.

A level or rank in an organization, profession, or society. / (cycling) A line of riders seeking maximum drafting in a crosswind, resulting in a diagonal line across the road.

(transitive, military) To form troops into an echelon.

(linear algebra) Of a matrix: having undergone Gaussian elimination with the result that the leading coefficient or pivot (that is, the first nonzero number from the left) of a nonzero row is to the right of the pivot of the row above it, giving rise to a stepped appearance in the matrix.

plural of echelon

(military) That part of an army that is not needed to directly combat the enemy. / (military, by extension) The administrative and supply departments of an army.

plural of rear echelon

(physics) A form of diffraction grating optimized for high orders of diffraction

plural of echelle