"gentleman," "cowboy," "knight;" "gentlemanly"
11th cent. From Late Latin caballarius "horseman," from Latin caballus "horse" (whence caballo) and -arius, an agent-forming suffix (see -ero).
Also the origin of the surnames Caballero, Caballeros.
Romance: Western Vulgar Latin: Asturian caballeru, Portuguese cavaleiro, Galician cabaleiro, Catalan cavaller, French chevalier, Italian cavaliere; Eastern Vulgar Latin: Romanian cavaler; Sardinian cabaglieri