'Acheron' originates from Greek, specifically the word 'Ἀχέρων', where 'ἄχος' meant 'pain' or 'grief'.

'Ἀχέρων' was adopted into Latin as 'Acheron', and eventually became the modern English word 'Acheron'.

Initially, it referred to a specific river in the underworld, but over time it evolved into a general term for any river of woe or sorrow.