The Spanish word 'caballo' (meaning 'horse') comes from the Latin word 'caballus', which specifically referred to a work horse or pack horse. This Latin term itself can be traced back to Ancient Greek 'καβάλλης' (kaballes), also meaning 'horse'. While Latin had another word 'equus' for horse in general, 'caballus' was the more common, colloquial term that survived in the Romance languages, including Spanish.

Several common Spanish words are derived from 'caballo', including 'caballero' (gentleman, horseman), 'caballeriza' (stable), and the more casual 'cabalgata' (horseback ride or parade). These words maintain their connection to horses while some, like 'caballero', have evolved to take on broader social meanings.

While English primarily uses Germanic-derived 'horse', there are several English words that share the same Greek-Latin root as 'caballo'. These include 'cavalry' (mounted soldiers), 'cavalier' (a horseman or knight, or someone showing casual disregard), and 'chivalry' (originally referring to horseman's behavior, now meaning courteous and honorable conduct). These words entered English through French, which also inherited the Latin 'caballus' root.