The Collaborative International Dictionary
Rear \Rear\, a. Being behind, or in the hindmost part; hindmost; as, the rear rank of a company.
Rear admiral, an officer in the navy, next in rank below a vice admiral and above a commodore. See Admiral.
Rear front (Mil.), the rear rank of a body of troops when faced about and standing in that position.
Rear guard (Mil.), the division of an army that marches in the rear of the main body to protect it; -- used also figuratively.
Rear line (Mil.), the line in the rear of an army.
Rear rank (Mil.), the rank or line of a body of troops which is in the rear, or last in order.
Rear sight (Firearms), the sight nearest the breech.
To bring up the rear, to come last or behind.
Wiktionary
n. (context military English) The rear rank of a body of troops when faced about and standing in that position.