The Spanish word 'mental' comes from the Latin word 'mentalis', which meant 'mental' or 'relating to the mind'. The Latin 'mentalis' was formed by combining two parts: the noun 'mens' meaning 'mind', and the suffix '-alis' meaning 'relating to'. This formation literally creates the meaning 'relating to the mind', which has remained remarkably stable as the word evolved from Latin to Spanish.

Some related Spanish words include 'mente' (mind), 'mentalmente' (mentally), and 'mentalidad' (mentality). All these words share the same Latin root 'mens' meaning 'mind'. The word 'mente' is particularly common and useful for Spanish learners, as it's both a noun meaning 'mind' and is used to form adverbs when added to adjectives (like 'rápidamente' meaning 'quickly').

The English word 'mental' is a direct cognate of the Spanish 'mental', as both come from the same Latin source 'mentalis'. Other related English words include 'mind' (though this comes from Germanic rather than Latin roots), 'mentality', 'mention', and even 'dementia' (which literally means 'away from the mind'). The similarity between Spanish and English 'mental' makes it an easy word for English speakers to remember.