An echelon formation () is a (usually

military A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct ...

) formation in which its units are arranged diagonally. Each unit is stationed behind and to the right (a "right echelon"), or behind and to the left ("left echelon"), of the unit ahead. The name of the formation comes from the French word échelon, meaning a rung of a ladder, which describes the shape that this formation has when viewed from above or below.

Military formation

Use of the formation dates back to ancient

infantry Infantry is a military specialization which engages in ground combat on foot. Infantry generally consists of light infantry, mountain infantry, motorized infantry & mechanized infantry, airborne infantry, air assault infantry, and mar ...

and cavalry warfare, as an alternative to column, line-abreast, or

phalanx The phalanx ( grc, φάλαγξ; plural phalanxes or phalanges, , ) was a rectangular mass military formation, usually composed entirely of heavy infantry armed with spears, pikes, sarissas, or similar pole weapons. The term is particularly ...

(box) formations. One of its earliest uses was at the

Battle of Leuctra The Battle of Leuctra ( grc-gre, Λεῦκτρα, ) was a battle fought on 6 July 371 BC between the Boeotians led by the Thebans, and the Spartans along with their allies amidst the post- Corinthian War conflict. The battle took place in the vici ...

, when the

Thebans Thebes (; ell, Θήβα, ''Thíva'' ; grc, Θῆβαι, ''Thêbai'' .) is a city in Boeotia, Central Greece. It played an important role in Greek myths, as the site of the stories of Cadmus, Oedipus, Dionysus, Heracles and others. Archaeolo ...

attacked the Spartan right with a column 48 men deep while their weaker center and right were repelled. The echelon formation may have been used by Hannibal at the Battle of Cannae,

Alexander the Great Alexander III of Macedon ( grc, Ἀλέξανδρος, Alexandros; 20/21 July 356 BC – 10/11 June 323 BC), commonly known as Alexander the Great, was a king of the ancient Greek kingdom of Macedon. He succeeded his father Philip II to ...

at the

Battle of Gaugamela The Battle of Gaugamela (; grc, Γαυγάμηλα, translit=Gaugámela), also called the Battle of Arbela ( grc, Ἄρβηλα, translit=Árbela), took place in 331 BC between the forces of the Army of Macedon under Alexander the Great ...

, Frederick II of Prussia, and the Confederate army at the

Battle of Gettysburg The Battle of Gettysburg () was fought July 1–3, 1863, in and around the town of Gettysburg, Pennsylvania, by Union and Confederate forces during the American Civil War. In the battle, Union Major General George Meade's Army of the Po ...

The tactic still persists and is regularly employed by all branches of the modern armed forces. Tactically, echelon formations are used because of the excellent range of vision offered to each participant in the formation. In particular, it is commonly employed by armored cavalry because of the large, overlapping fields of fire that it gives to each

tank A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engi ...

in the formation, and by combat aircraft, allowing them to communicate visually and maneuver as a single unit. USAF_Fighter_School_Acrojets_demonstration_team_-_1950

USAF_Fighter_School_Acrojets_demonstration_team_-_1950

"Echeloning" is the name of a tactic in use by the United Kingdom's armed forces, mainly the

. It consists of using a company to attack a set of positions. Once the first platoon in the company has reached its limit of advance (ammunition has been expended, fatigue has become high, or casualties are mounting) another

platoon A platoon is a military unit typically composed of two or more squads, sections, or patrols. Platoon organization varies depending on the country and the branch, but a platoon can be composed of 50 people, although specific platoons may rang ...

"echelons through" it to continue onto the next position. The tactic is similar to leapfrogging. Echelon formations are also commonly used by civic or

riot police Riot police are police who are organized, deployed, trained or equipped to confront crowds, protests or riots. Riot police may be regular police who act in the role of riot police in particular situations or they may be separate units organize ...

to move crowds either to the left or right. ''En echelon'' is also used for a type of arrangement of gun turrets on ships: see .

Derived meanings

The name has been adopted by the

birdwatching Birdwatching, or birding, is the observing of birds, either as a recreational activity or as a form of citizen science. A birdwatcher may observe by using their naked eye, by using a visual enhancement device like binoculars or a telescope, by ...

community to describe the familiar V-shaped formations of flights of

geese A goose ( : geese) is a bird of any of several waterfowl species in the family Anatidae. This group comprises the genera '' Anser'' (the grey geese and white geese) and ''Branta'' (the black geese). Some other birds, mostly related to the she ...

duck Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a form ...

s and other

migratory birds Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by ...

, though this more symmetric formation is more strictly defined as a

V formation A V formation is the symmetric V-shaped flight formation of flights of geese, swans, ducks, and other migratory birds, improving their energy efficiency. Usually, large birds fly in this formation since smaller birds create more complex wind c ...

. In geology, ''en echelon'' describes an arrangement where a set of short linear features overlap or are staggered in a line that runs obliquely to the strike of the individual features.

Echelon faults ECHELON, originally a secret government code name, is a surveillance program (signals intelligence/SIGINT collection and analysis network) operated by the five signatory states to the UKUSA Security Agreement:Given the 5 dialects that use ...

and

en echelon veins In structural geology, en échelon veins, "en échelon gash fractures" or "Tiger Stripes" are structures within rock caused by noncoaxial shear. En echelon veins can be parallel or subparallel, closely-spaced, overlapping or step-like minor str ...

are examples. In sheet material response to

shear stress Shear stress, often denoted by (Greek: tau), is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. ''Normal stress'', on the ...

it is typical for a series of

echelon cracks Echelon cracks are a related series of cracks in a planar structure and are a response to shearing forces in the plane of the surface. Such cracks are typically found in asphalt roadways due to aseismic creep and in other planar structures such as w ...

to form. This is commonly seen in asphalt roads subject to shear stress imposed by aseismic fault creep. In mathematics, the term row echelon form refers to a kind of matrix where the non-zero elements are shaped in an echelon-like manner. In road bicycle racing, an echelon formation is a diagonal line of racers, which allows cooperative drafting in crosswinds.

References

{{reflist Tactical formations Ornithology Structural geology