'demythicize' originates from Modern English, formed from the prefix 'de-' (from Latin 'de-' meaning 'away, off'), 'myth' (from Greek 'mythos' meaning 'story, legend'), and the suffix '-ize' (from Greek '-izein' via Latin/Old French meaning 'to make or to do').

'demythicize' developed in the 20th century in English, influenced by earlier scholarly and theological terms such as German 'entmythologisieren' / 'demythologize'; the element 'myth' comes via Old French/Latin forms of Greek 'mythos', and the modern verb was formed by adding English productive prefix and suffix to 'myth'.

Initially coined in scholarly/theological contexts to mean 'to remove mythological interpretation from religious texts', it now broadly means 'to remove mythic elements or interpretations' and is used in literary, historical, and critical contexts as well.