The Spanish word 'arandela', meaning 'washer' or 'round disk', has an interesting journey through Romance languages. It begins with the Latin word 'rotundus' meaning 'round', which evolved into Vulgar Latin 'retundus'. This then developed into French 'rond' (also meaning 'round'), which gave rise to the French word 'rondelle' meaning 'washer' or 'small round object'. The Spanish 'arandela' was borrowed from this French term, maintaining the meaning of a circular, disk-like object used in machinery.

Some related Spanish words include 'redondo' (round) and 'ronda' (round, circuit), which come from the same Latin root 'rotundus'. These words share the basic concept of roundness or circular shape with 'arandela', though they're used in different contexts.

English speakers might recognize the connection to words like 'round' and 'rotund', which also derive from Latin 'rotundus'. The word 'rondelle', used in cooking to describe round slices of vegetables, is a direct borrowing from French and is related to 'arandela'. Even the word 'rotunda' (a round building or hall) shares this ancient connection to the concept of roundness.