GARRISON, in the art of war, a body of forces, disposed in a fortress, to defend it against the enemy, or to keep the inhabitants in subjection: or even to be subsisted during the winter season: hence garrison and winter quarters are sometimes used indifferently for the same thing; and sometimes they denote different things. In the latter case, a garrison is a place wherein forces are maintained to secure it, and where they keep regular guard, as a frontier town, a citadel, castle, tower, &c. The garrison should be always stronger than the towns-men.
Du Cange derives the word from the corrupt Latia garnisio, which the latter writers use to signify all manner of munition, arms, victuals, &c. necessary for the defence of a place, and sustaining of a siege.
Winter quarters signify a place where a number of forces are laid up in the winter season, without keeping the regular guard.