'autocrator' originates from Greek, specifically the word 'αὐτοκράτωρ' (autokrátōr), where the prefix 'auto-' meant 'self' and the root 'kratos/kratein' meant 'rule' or 'to have power'.

'autocrator' passed from Byzantine/Koine Greek 'αὐτοκράτωρ' into Medieval and Late Latin as 'autocrator', and was adopted into English and scholarly usage (especially in works on Byzantine history) largely unchanged.

Initially, it meant 'one who rules by himself' or 'self-ruler' (a sovereign exercising sole power); over time it maintained this core sense but came to be used mainly as a technical or historical term rather than as a modern political title.