The Spanish verb 'escalar' (to climb) comes from the Latin word 'scalaris' meaning 'relating to stairs', which itself derives from the Latin noun 'scala' meaning 'ladder' or 'stairs'. The Spanish infinitive verb ending '-ar' was added to create the modern verb. This etymology makes intuitive sense since climbing often involves going up something step by step, like stairs or a ladder.

Some related Spanish words include 'escalera' (stairs/ladder), 'escalón' (step/stair), and 'escala' (scale/ladder). All these words share the same Latin root 'scala' and relate to the concept of ascending or measuring in steps.

English speakers might recognize the connection to words like 'scale' (both in the sense of climbing/ascending and in measurement), 'escalator' (moving stairs), and 'escalate' (to increase gradually). These English words also trace back to the Latin 'scala'. The connection between climbing, stairs, and gradual increase is preserved across both languages.