'bacchanalia' originates from Latin, specifically the word 'Bacchanalia', which referred to festivals of the god 'Bacchus' (the Roman name for Dionysus).

'bacchanalia' comes from Latin 'Bacchanalia' (plural of 'Bacchanalium'), which in turn relates to 'Bacchus' (from Greek 'Bakkhos' / 'Bakchos'); the term moved from Latin into Middle English and Modern English as 'bacchanalia'.

Initially, it meant 'festivals or rites in honor of Bacchus' (religious/ritual). Over time it evolved to mean 'wild, drunken revelry' or any unrestrained orgy-like celebration.