noun an original (book or document).
2. authentic ·noun authoritative.
3. authentic ·noun vested with all due formalities, and legally attested.
4. authentic ·noun of approved authority; true; trustworthy; credible; as, an authentic writer; an authentic portrait; authentic information.
5. authentic ·noun having as immediate relation to the tonic, in distinction from plagal, which has a correspondent relation to the dominant in the octave below the tonic.
6. authentic ·noun having a genuine original or authority, in opposition to that which is false, fictitious, counterfeit, or apocryphal; being what it purports to be; genuine; not of doubtful origin; real; as, an authentic paper or register.