'cretic' originates from Latin, specifically the word 'crēticus', which itself comes from Ancient Greek 'krētikós', where 'krētikós' meant 'Cretan'.

'crēticus' (Latin) passed through scholarly use and was adopted into English as 'cretic', eventually becoming the modern English word 'cretic'.

Initially, it meant 'Cretan', but over time it evolved into its current technical sense of 'a metrical foot (long–short–long), and by extension, pertaining to that foot'.