a station established at a distance from the main body of an army to protect it from surprise attack: We keep only a small garrison of men at our desert outposts.
Definition: 2
the body of troops stationed there; detachment or perimeter guard.
Definition: 3
an outlying settlement, installation, position, etc.
Definition: 4
(military) a position stationed at a distance from the area occupied by a major formation the troops assigned to such a position