'atrament' originates from Latin, specifically the word 'atramentum', where 'ater' meant 'black'.

'atrament' changed from Late Latin/Medieval Latin 'atramentum' (and was used in Old French and Middle English forms) and eventually became the modern English word 'atrament'.

Initially it meant 'a black substance used for writing (ink)'; over time the core meaning has remained but the word has become archaic in modern English, surviving mainly in literary or historical contexts.