'dolor' originates from Latin, specifically the word 'dolor' (from the verb 'dolēre'), where 'dolēre' meant 'to feel pain or to grieve'.

'dolor' passed from Latin into Old French/Anglo-Norman (forms like 'dolor'/'dolour') and then into Middle English as 'dolour' or 'dolor', eventually appearing in modern English as 'dolor' (and the variant 'dolour').

Initially, it meant 'pain' or 'sorrow' in Latin; over time in English it has become chiefly literary for 'sorrow' while retaining occasional technical or archaic senses of 'pain'.