attestation

Short definition from Wiktionary

Noun

1. 1
   A thing that serves to bear witness, confirm, or authenticate; validation, verification, documentation.
2. 2
   A confirmation or authentication.
3. 3
   The process, performed by accountants or auditors, of providing independent opinion on published financial and other business records of an enterprise, public agency, or other organization.
4. 4
   An appearance in print or otherwise recorded on a permanent medium.