The Spanish word 'afición' (meaning 'fondness' or 'hobby') comes from the Latin word 'affectio' meaning 'influence' or 'disposition'. This Latin word was formed by combining the verb 'afficere' ('to affect' or 'influence') with the suffix '-tio' (which forms action nouns). Going back further, 'afficere' itself was created from two parts: the prefix 'ad-' meaning 'toward' or 'near', and the verb 'facere' meaning 'to do' or 'to make'.

The semantic evolution from 'influence/disposition' to 'fondness/hobby' makes sense - something that influences or affects you strongly can become something you're fond of or passionate about.

Some related Spanish words include 'afecto' (affection), 'afectar' (to affect), and 'aficionado' (enthusiast, fan). All these words share the same Latin roots and maintain the connection to feelings, influence, and passionate interest.

English speakers might recognize the connection to words like 'affect', 'affection', and even 'affect' (as a psychological term for emotion or feeling). The word 'aficionado' has also been borrowed directly from Spanish into English to describe an enthusiast or expert. All these words trace back to the same Latin roots of 'ad-' + 'facere'.