authenticate

UK: /ɔːˈθɛntɪkeɪt/ US: /ɔˈθɛntɪˌkeɪt/ ,(ô then′ti kāt′)

Inflections of 'authenticate' (v): (⇒ conjugate)

authenticates

v 3rd person singular

authenticating

v pres p

authenticated

v past

authenticated

v past p

WordReference Random House Learner's Dictionary of American English © 2026

au•then•ti•cate /ɔˈθɛntɪˌkeɪt/   v. [~ + object] , -cat•ed, -cat•ing. 

1. to establish (something) as genuine, real, or true:
   The signature was not authenticated.
2. to establish or prove conclusively the origin of (a painting, book, etc.):
   to authenticate a painting.

au•then•ti•ca•tion /ɔˌθɛntɪˈkeɪʃən/  n. 

[uncountable] The signature is subject to authentication.

[countable* usually singular]

I need an authentication on a credit card, please.

WordReference Random House Unabridged Dictionary of American English © 2026

au•then•ti•cate  (ô then′ti kāt′), v.t., -cat•ed, -cat•ing. 

1. to establish as genuine.
2. to establish the authorship or origin of conclusively or unquestionably, chiefly by the techniques of scholarship:
   to authenticate a painting.
3. to make authoritative or valid.

• Medieval Latin authenticātus made authentic (past participle of authenticāre). See authentic, -ate¹
• 1565–75

au•then′ti•cat′a•ble, adj. 
au•then′ti•ca′tion, n. 
Synonyms

• 1. confirm, validate, substantiate.

Collins Concise English Dictionary © HarperCollins Publishers::

authenticate / ɔːˈθɛntɪˌkeɪt/ verb (transitive)

1. to establish as genuine or valid
2. to give authority or legal validity to

auˌthentiˈcation noun

auˈthentiˌcator noun