'mythic' originates from Medieval Latin/Modern Latin, specifically the word 'mythicus', ultimately from Greek 'mythikos' (from 'mythos').

'mythos' in Greek meant 'word, story, tale' and passed into Latin as 'mythicus' and later became the English adjective 'mythic' (formed by combining 'myth-' with the suffix '-ic').

Initially, it meant 'pertaining to myths or stories'; over time the sense broadened to include 'legendary, epic, or larger-than-life' usages in modern English.