'authentication' originates from Late Latin, specifically the word 'authenticatio', where the root derived from Greek 'authentikós' (related to 'authentēs') meant 'author' or 'genuine'.

'authentication' changed from Medieval/Latin forms: Greek 'authentēs' → Greek adjective 'authentikós' → Late Latin 'authenticatio' → Old/Medieval French forms and then into Middle English as 'authentication', eventually becoming the modern English 'authentication'.

Initially, it meant 'the act of authorizing or declaring something genuine', and over time it has retained that core sense while expanding into technical senses (e.g., computing identity verification).