An army post is a military installation, typically consisting of a BASE, FORT, or camp. The term 'SENTRY' (6 letters) refers to a soldier who stands guard at a military installation, while 'ORD' (3 letters) is an acronym for the U.S. Army's Ordnance Corps, which is responsible for the supply and maintenance of weapons and ammunition. A 'FORT' (4 letters) is a fortified military structure, and a 'BASE' (4 letters) is a military facility from which operations are conducted. All of these terms are used to describe an army post.