1.  squadron(n = noun.group) - a cavalry unit consisting of two or more troops and headquarters and supporting arms;
is a kind of cavalry

2.  squadron(n = noun.group) - an air force unit larger than a flight and smaller than a group;
is a kind of air unit
is a member of wing
has particulars: escadrille

3.  squadron(n = noun.group) - a naval unit that is detached from the fleet for a particular task;
is a kind of naval unit
has particulars: escadrille

1.  Primarily, a square; hence, a square body of troops; a body of troops drawn up in a square. [1913 Webster]
"Those half-rounding quards
Just met, and, closing, stood in squadron joined." [1913 Webster]

2.  A body of cavalry comprising two companies or troops, and averaging from one hundred and twenty to two hundred men. [1913 Webster]

3.  A detachment of vessels employed on any particular service or station, under the command of the senior officer; as, the North Atlantic Squadron. Totten. [1913 Webster]

squadron, n.
1 an organized body of persons.
2 a principal division of a cavalry regiment or armoured formation, consisting of two troops.
3 a detachment of warships employed on a particular duty.
4 a unit of the Royal Air Force with 10 to 18 aircraft.

Idiom:
Squadron Leader the commander of a squadron of the Royal Air Force, the officer next below Wing Commander.

Etymology:
It. squadrone (as SQUAD)

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