'coeducationalism' originates from modern English, formed from the prefix 'co-' (from Latin 'com' meaning 'together'), the adjective 'coeducational' (from 'co-' + 'educational'), and the suffix '-ism' (from Greek/Latin indicating 'practice, system, or ideology').

'coeducationalism' developed by adding the suffix '-ism' to 'coeducational' (itself from 'coeducation' + adjectival formation). The noun 'coeducation' appeared in the 19th century to describe mixed schooling, and the -ism derivative arose later to denote the system or doctrine.

Initially it referred primarily to the practice of educating males and females together; over time it also came to be used for the doctrine or advocacy (the ideological aspect) of that practice.