The Spanish word 'semejante' (meaning 'similar') comes from the Latin word 'similantem', which was the accusative form of 'similans' meaning 'being similar'. This in turn came from the Latin adjective 'similis', which meant 'similar' or 'like'. The evolution from Latin to Spanish shows typical sound changes, where the Latin 'i' shifted to 'e' and the 'l' transformed into a 'j' sound in Spanish.

Some related Spanish words include 'semejanza' (similarity), 'semejar' (to resemble), and 'asemejar' (to make similar). All these words share the same Latin root and maintain related meanings around the concept of similarity or resemblance.

English speakers might recognize the connection to words like 'similar' and 'simulate', which come from the same Latin root 'similis'. The word 'same' is also distantly related, though it comes from a Germanic rather than Latin source. Understanding these connections can help remember that 'semejante' deals with similarity or resemblance.