Historically, cavalry (from the French word cavalerie, itself derived from "cheval" meaning "horse") are soldiers or warriors who fight mounted on horseback. Cavalry were the most mobile of the combat arms, operating as light cavalry in the roles of reconnaissance, screening, and skirmishing in many armies, or as heavy cavalry for decisive shock attacks in other armies. An individual soldier in the cavalry is known by a number of designations depending on era and tactics, such as cavalryman, horseman, trooper, cataphract, knight, hussar, uhlan, mamluk, cuirassier, lancer, dragoon, or horse archer. The designation of cavalry was not usually given to any military forces that used other animals for mounts, such as camels or elephants. Infantry who moved on horseback, but dismounted to fight on foot, were known in the early 17th to the early 18th century as dragoons, a class of mounted infantry which in most armies later evolved into standard cavalry while retaining their historic designation.