(n.) The act of certifying.

John Hancock OK acceptance affidavit affirmance affirmation approbation approval ascertainment assurance attestation authentication authority authorization backing backing up bearing out bill of health bolstering buttressing certificate certificate of proficiency check checking circumstantiation clearance collation confirmation corroboration corroboratory evidence countenance countersignature credential deposition determination diploma documentation empowerment enabling endorsement enfranchisement ensuring entitlement establishment fiat fortification go-ahead green light imprimatur navicert nod notarization notarized statement note okay permission proof proving proving out ratification reassurance reassurement reinforcement rubber stamp sanction seal sheepskin sigil signature signet stamp stamp of approval statement under oath strengthening subscription substantiation support supporting evidence swearing sworn statement sworn testimony testamur testimonial testimony the nod ticket undergirding validation verification visa vise voucher vouching warrant warranty witness