Echelon comes from the French, 'échelon', meaning a rung of a ladder. It usually refers to Echelon formation, a formation in aerial combat, tank warfare, naval warfare and medieval warfare; also used to describe a migratory bird formation. Each element of the formation (on one wing of the echelon) will be both further out from the lead element and further back than the preceding element.
The acronym, ECHELON, refers to an intelligence gathering network run by an international alliance of signals intelligence organizations known as UKUSA.
Other meanings include:
