'demythologize' originates from Greek elements and modern English formation: the prefix 'de-' (from Latin via French) meaning 'remove' or 'reverse' combined with 'mythology' (from Greek 'mythos' meaning 'story' or 'legend' + Greek 'logos' meaning 'word, account, study'), with the verb-forming suffix '-ize' meaning 'to make' or 'to render'.

'mythos' entered English via Latin and Old French as part of 'mythology'; 'mythologize' developed in English to mean 'to treat as myth' or 'to relate as myth'; the formation 'demythologize' (and related noun 'demythologization') appears in modern theological and literary discourse (notably mid-20th century) to denote removing mythic interpretation.

Initially the components referred simply to 'story' and 'study' (myth + study) and the later compound meant 'to treat in terms of myth'; over time 'demythologize' came to mean not only 'remove myth' but also 'reinterpret symbolic or mythic language to reveal underlying non-mythical meaning' (as in theological demythologizing).