Flankers
Flankers (French “flanqueurs”), individual cavalrymen or foot soldiers (skirmishers) who are sent forward by formed bodies of troops to observe the enemy‘s movements and to screen their own. In order to evade enemy fire, they make arc-shaped advances, e.g. in the form of a figure-8, which is called flanking. In the cavalry, every regiment normally had appropriately armed and trained men, even if flanking was considered the domain of the light cavalry. In the infantry, jägers, riflemen, füsiliers, voltigeurs, grenadiers, light infantrymen and flank grenadiers were preferred as flankers, as they were better trained for skirmish combat “en tirailleurs” than the regular musketeer.
Source: Meyers Großes Konversations-Lexikon, 6. Auflage 1905–1909