The extreme left or right of a military formation. The following is an extract:

Flank attack (Mil.), an attack upon the side of an army or body of troops, distinguished from one upon its front or rear.

Flank company (Mil.), a certain number of troops drawn up on the right or left of a battalion; usually grenadiers, light infantry, or riflemen.

Flank defense (Fort.), protection of a work against undue exposure to an enemy's direct fire, by means of the fire from other works, sweeping the ground in its front.

Flank en potence (Mil.), any part of the right or left wing formed at a projecting angle with the line.

Flank files, the first men on the right, and the last on the left, of a company, battalion, etc.

Flank march, a march made parallel or obliquely to an enemy's position, in order to turn it or to attack him on the flank.

Flank movement, a change of march by an army, or portion of one, in order to turn one or both wings of the enemy, or to take up a new position.

Flanks of a frontier, salient points in a national boundary, strengthened to protect the frontier against hostile incursion.

Flank patrol, detachments acting independently of the column of an army, but patrolling along its flanks, to secure it against surprise and to observe the movements of the enemy.

When you get to work before someone and leave after them.

The section of flesh on the body of a person or an animal between the last rib and the hip; the side.

In a video game, flanking means when you are going behind an opponent, or when someone is coming behind you.

To have a floppy wank.

The fat that dangles off of your sides, or the fat in general. This may also be called Love Handles, or side fat.

A sexual gropage of the calf.

Soft, pink and silky smooth pussy lips.

The maneuver OAP's pull at bus stops in order to get to the front of the queue. Normally involves large groups of them mobbing their way into the side of orderly queues.