'Dionysian' originates from Greek, specifically the word 'Dionysos', where 'Dio-' meant 'of Zeus' (from 'Dios') and 'Nysa' was the name of a mythical place associated with the god.

'Dionysian' changed from the Latin/Latinized forms such as 'Dionysius' and entered English in late Middle/early Modern usage as 'Dionysian', derived ultimately from Greek 'Dionysos'.

Initially, it meant 'of or pertaining to the god Dionysus'; over time (especially in literary and philosophical usage, e.g. Nietzsche) it broadened to mean 'relating to ecstatic, irrational, or creative impulses' beyond the strictly religious sense.