'authoriser' originates from Old French, specifically the word 'autoriser', where 'autor-' (from Latin 'auctor') meant 'author, originator' or 'one who gives authority'.

'authoriser' changed from the Old French word 'autoriser' and the Middle English form 'authorisen', and eventually became the modern English noun 'authoriser' (also spelled 'authorizer' in US English).

Initially related to 'author' or 'originator' (one who gives authority), but over time its sense narrowed to 'to give official permission' and so the noun came to mean 'one who grants permission or approval'.