caballus

The Latin word caballus started life as a humble term — not the noble equus of poetry and cavalry parades, but a workhorse, a nag, the kind of beast that hauled packs. Yet it was exactly this everyday word that survived into the spoken Latin of the streets and conquered the Romance languages. Equus stayed in the books; caballus became the living word for 'horse.'

From there it split along two roads — one through Italy, one through France — and arrived in English wearing two different coats.

The Italian road: cavallo. From cavallo came cavalleria, the body of soldiers who fought on horseback. English borrowed it (via French cavalerie) as cavalry — literally 'horse-soldiers.' The rider himself was a cavaliere, which English took as cavalier: first a gallant horseman or a Royalist knight, then, by a sharp twist, an adjective meaning 'haughty, dismissive' — because the mounted gentleman looked down on the foot-soldiers below him. Look up at a man on a horse and you can feel the arrogance; that downward glance is the whole story of the word's slide from 'knight' to 'couldn't-care-less.' A procession of such riders was a cavalcade — a column of horses on the march, a meaning that later widened to any impressive procession or series.

The French road: cheval. French turned caballus into cheval, and from cheval came chevalier, the knight. The whole institution of knighthood — the code of honor, courage, and courtesy — became chivalry, and the adjective for a man who lives by that code is chivalrous. Notice that cavalry and chivalry are, at root, the same word: both are 'horse-soldiery.' One kept the military meaning; the other floated up into the realm of ideals.

The runaway clipping: cab. The strangest member sits a little apart. A cabriolet was a light, two-wheeled, one-horse carriage — named from French cabrioler 'to leap, caper,' because it bounced about like a leaping goat. The word was clipped to cab, came to mean a horse-drawn carriage for hire, and then — when the horse vanished and the engine arrived — simply stuck to the motor taxi. (The driver's compartment of a truck or train is the same word.) The horse is long gone, but the name of the cab still carries it.

The pattern, then: one lowly Latin packhorse, two language routes, and a family that ranges from battlefield (cavalry) to ideal (chivalry) to attitude (cavalier) to a yellow taxi (cab).