'historian' originates from Greek, specifically the word 'historia' (ἱστορία), via Latin 'historia' and Old French 'estoire'/'histoire'. The English agent-forming suffix '-an' was added to form 'historian'.

'historia' (Greek: 'inquiry, knowledge acquired by investigation') passed into Latin as 'historia', into Old French as 'estoire'/'histoire', then into Middle English as 'history'. The agent noun 'historian' was formed in English by adding '-an' to 'history'.

Initially it meant 'inquiry' or 'a narrative of past events'; over time the focus shifted to the account of past events and then to a person who researches or writes those accounts—hence 'historian' as 'one who studies or records history'.