The Spanish word 'válido' (meaning 'valid') comes from the Latin word 'validus' meaning 'strong' or 'powerful'. This Latin word was formed by combining the verb 'valere' ('to be strong, to be well') with the adjective suffix '-idus'. The meaning evolved from physical strength to the more abstract sense of being legally or logically sound that we see in modern Spanish.

Several common Spanish words share this Latin root 'valere', including 'valer' (to be worth), 'valor' (value, courage), and 'valiente' (brave). You can see how all these words connect to the original meaning of strength or worth.

Many English words are related to 'válido' through the same Latin root, including 'valid', 'value', 'valor', and 'valiant'. The English word 'valid' is particularly close in both meaning and form to the Spanish 'válido'. Another interesting connection is 'equivalent' (equal in value) and 'prevail' (to prove stronger than others).