Echelon /(ĕsh"e*lŏn)/

Ech·e·lon

Echelon

n.
  1. An arrangement of a body of troops when its divisions are drawn up in parallel lines each to the right or the left of the one in advance of it, like the steps of a ladder in position for climbing. Also used adjectively; as, echelon distance. (Mil.)
  2. An arrangement of a fleet in a wedge or V form. (Naval)

Phrases & Compounds
Echelon lens
a large lens constructed in several parts or layers, extending in a succession of annular rings beyond the central lens; -- used in lighthouses.

Echelon

v. t.
  1. To place in echelon; to station divisions of troops in echelon. (Mil.)

Echelon

v. i.
  1. To take position in echelon.
    Change direction to the left, echelon by battalion from the right.