Young Reddish Blonde Girl Outside With A Knight's Helmet And A Horse

An Equestrian (Latin, from eques "horseman", from equus "horse") was a member of the second highest social class in the Roman Republic and early Roman Empire. This class is often translated as "knight"; the medieval knight, however, was called miles in Latin, (which in classical Latin meant "soldier", normally infantry).
In the later Roman Empire the classical Latin word for horse, equus, was replaced in common parlance by vulgar Latin caballus, sometimes thought to derive from Gaulish caballos. From caballus arose terms in the various Romance languages cognate to the (French-derived) English cavalier: Old Italian cavaliere, Italian cavallo, French cheval, Spanish caballero, French chevalier, Portuguese cavaleiro, Romanian cavaler. The Germanic languages prefer terms cognate to the English rider: German Ritter, and Dutch and Scandinavian ridder.