The Spanish word 'último' (meaning 'last' or 'final') comes from the Latin word 'ultimus', which meant 'farthest' or 'last'. The Latin word was formed by combining two parts: the root 'uls' meaning 'beyond' and the suffix '-imus' which was used to form superlatives in Latin. So literally, 'ultimus' meant 'the most beyond' or 'the farthest', which naturally evolved to mean 'last' or 'final' as we use it in Spanish today.

While 'último' itself is a commonly used Spanish word, you might encounter it in various forms like 'ulterior' (ulterior, further) and 'ultra-' (as a prefix meaning 'beyond' or 'extremely'), which all share the same Latin root 'uls' meaning 'beyond'.

English speakers might recognize the connection to words like 'ultimate' and 'ulterior', which come from the same Latin source. 'Ultimate' preserves much of the original meaning as it refers to the final or last instance of something, while 'ulterior' (as in 'ulterior motive') carries the sense of something that lies beyond or is further away. The prefix 'ultra-' in English (as in 'ultraviolet' or 'ultra-modern') also comes from this same Latin root, meaning 'beyond' or 'extremely'.