Authenticate

1. v. t. To prove authentic; to determine as real and true; as, to authenticate a portrait.
2. v. t. To render authentic; to give authority to, by the proof, attestation, or formalities required by law, or sufficient to entitle to credit.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.