The Spanish word 'atomismo' (meaning 'atomism') comes from Latin 'atomismus', which was formed from Greek elements. It combines the Greek word 'atomos' meaning 'indivisible' with the suffix '-ismos' meaning 'doctrine or system'. The word 'atomos' itself is made up of 'a-' meaning 'not, without' and 'tomos' meaning 'cut, divided' (from the verb 'temnein' - 'to cut'). So literally, atomismo refers to the philosophical doctrine of that which cannot be cut or divided further.

A simpler related Spanish word is 'átomo' (atom), which comes directly from the same Greek root 'atomos'. While 'atomismo' refers to the theoretical system or doctrine about atoms, 'átomo' refers to the fundamental particle itself.

Several English words share this Greek origin, including 'atom' and 'atomic'. The English word 'tome' (meaning a large or scholarly book) comes from Greek 'tomos' (something cut or divided), as books were originally made by cutting and dividing scrolls or papers. The prefix 'a-' meaning 'not' or 'without' is found in many English words like 'amoral' or 'asexual', while the suffix '-ism' (from Greek '-ismos') is extremely common in English words denoting systems of thought or practice, like 'capitalism' or 'Buddhism'.