The Spanish verb 'semejar' (meaning 'to resemble' or 'to be similar to') comes from the Latin word 'similis', meaning 'similar' or 'like'. The Latin word evolved through its neuter plural form 'similia' (meaning 'similar things'), which developed into the Spanish noun 'semeja' (meaning 'likeness'). The verb 'semejar' was then formed by adding the Spanish infinitive suffix '-ar' to 'semeja'.

This evolution shows how a Latin adjective meaning 'similar' eventually became the basis for a Spanish verb meaning 'to resemble', with the intermediate step of becoming a noun meaning 'likeness'.

Several common Spanish words are related to 'semejar', including 'semejante' (similar, alike), 'semejanza' (similarity, resemblance), and the adjective 'similar'. All these words share the same Latin root 'similis' and form a family of words relating to similarity and resemblance in Spanish.

English speakers might recognize the connection to words like 'similar' and 'simulate', which also come from Latin 'similis'. The English word 'similar' maintains almost the exact same meaning as its Latin ancestor, while 'simulate' developed to mean 'to imitate or reproduce the appearance or characteristics of something' - a meaning closely related to resemblance. Another related English word is 'semblance', meaning 'the outward appearance or apparent form of something', which shares the same etymological root.