'atomism' originates from modern English, formed from the noun 'atom' plus the suffix '-ism'; 'atom' ultimately comes from Greek 'atomos' where 'a-' meant 'not' and 'tomos' (from 'temnein') meant 'to cut'.

'atomism' developed via Medieval and early modern scholarly usage: Greek 'atomos' passed into Latin and Medieval Latin as 'atomus'/'atomismus', appeared in French as 'atomisme', and was adopted into modern English as 'atomism' in the 17th century.

Initially, it referred specifically to the idea of 'uncuttable' particles (the notion of indivisible atoms); over time the term broadened to denote scientific atomic theories and, by extension, any doctrine or method that explains wholes by their discrete parts (reductionism/methodological atomism).