FLANK n. 2 definitions
The side of an army, or of any division of an army, as of a brigade, regiment, or battalion; the extreme right or left; as, to attack an enemy in flank is to attack him on the side. When to right and left the front Divided, and to either flank retired. Milton.
GRENADIER n.
who carried and threw grenades; afterward, one of a company attached to each regiment or battalion, taking post on the right of the line, and wearing a peculiar uniform. In modern times, a member of a special regiment or corps; as, a grenadier of the guard of Napoleon I. one of the regiment of Grenadier Guards of the…