something which validates or confirms the authenticity of something / (computing) proof of the identity of a user logging on to some network / a hallmark or assay-mark on a piece of metalwork

plural of authentication

Of the same origin as claimed; genuine. / Conforming to reality and therefore worthy of trust, reliance, or belief. / (music, of a Gregorian mode) Having the final as the lowest note of the mode.

The quality of being genuine or not corrupted from the original, of having the same origin (or attribution, commitment, intention, etc.) as claimed.

The quality of being authentic; authenticity.

(civil law) A collection of the Novels or New Constitutions of Justinian, by an anonymous author.

(archaic) Authentic.

In an authentic manner; with the requisite or genuine authority.

(transitive) To render authentic; to give authority to, by the proof, attestation, or formalities required by law, or sufficient to entitle to credit.

Synonym of authentic.