Garrison n. : A body of troops stationed in a fort or fortified town.

Garrison n. : A fortified place, in which troops are quartered for its security.

Garrison v. t. : To place troops in, as a fortification, for its defense; to furnish with soldiers; as, to garrison a fort or town.

Garrison v. t. : To secure or defend by fortresses manned with troops; as, to garrison a conquered territory.

Example:
What was the average size of a castle Garrison in the Late Middle Ages?

Taxonomy
Garrison, free encyclopedia, British garrison, Garrison town, military barracks, Garrison Sergeant Major, search, spellings, the French, garnison, collective term, body, guard, home base, city, castle, 1st Battalion, 1st Infantry.

Defination from the web:
Garrison (various spellings) (from the French garnison, itself from the verb garnir, "to equip") is the collective term for a body of troops ... or camp and their own military headquarters, usually commanded by a Colonel, Brigadier or Major-General, assisted by a Garrison Sergeant Major. ...