sortie

Sortie comes from French sortir, meaning 'to go out, to exit.' A sortie was, in its simplest form, an exit — the act of going out. In military French, a sortie was a sudden offensive movement by besieged troops, bursting out of their fortified position to attack the besiegers. The word entered English in the late 1700s with this specific meaning: a defensive force taking the fight to the attackers by leaving the safety of their walls.

The sortie was a standard tactic of siege warfare. A garrison surrounded and under pressure could launch a sortie at dawn or at night, targeting the enemy's siege works, destroying their trenches, spiking their cannons, and withdrawing before the enemy could organize a response. Success bought time. Failure lost men the garrison could not replace. The sortie was a gamble — the defensive equivalent of doubling down.

Aviation adopted the word in World War I. A sortie became a single operational flight by a single aircraft. One plane, one mission, one sortie. The word was convenient because it counted effort rather than outcome: an air force might fly 500 sorties in a day regardless of whether any individual sortie achieved its objective. The word measured activity, not success.

In modern military English, sortie almost exclusively means an air mission. The ground-combat meaning — troops bursting out of a besieged position — has faded because siege warfare itself has faded. The word that meant 'going out' still means going out, but now it is a plane leaving a runway rather than soldiers leaving a fortress. The exit is the same. The medium is different.