A sortie (from the French word meaning exit or from Latin root surgere meaning to "rise up") is a deployment or dispatch of one military unit, be it an aircraft, ship, or troops, from a strongpoint.
In siege warfare, the word sortie refers specifically to a sudden sending of troops against the enemy from a defensive position—that is, an attack launched against the besiegers by the defenders.
Purposes of sorties include harassment of enemy troops, destruction of siege weaponry and engineering works,[2] joining the relief force, etc.
Sir John Thomas Jones, analyzing a number of sieges carried out during the Peninsular War (1807–1814), wrote:[3] The events of these sieges show that a bold and vigorous sortie in force might carry destruction through every part of a besieger's approaches, where the guard is injudiciously disposed and ill commanded; but that if due precautions have been observed in forming the approaches and posting the defenders, any sortie from a besieged place must be checked with loss in their advance, when the approaches are still distant; or when the approaches are near, should a sortie succeed in pushing into them by a sudden rush, the assailants must inevitably be driven out again in a moment, with terrible slaughter.In military aviation, a sortie is an aircraft flight or mission (training or combat),[4] starting when the aircraft takes off.
For example, one mission involving six aircraft would tally six sorties.