Primarily, a square; hence, a square body of troops; a body of troops drawn up in a square.
- A naval unit consisting of two or more divisions of a fleet.
- An armored cavalry unit subordinate to a regiment and consisting of two or more troops.
- A cavalry or armored unit of a European army, corresponding to a company.
- A basic tactical air force unit, subordinate to a group and consisting of two or more flights.
- A multitude or horde: "Squadrons of flies like particles of dust danced up and down” ( T.E. Lawrence).