ETYM Late Lat. affidavit he has made oath, perfect tense of affidare. Related to Affiance, Affy.
A sworn statement in writing; a declaration in writing, signed and made upon oath before an authorized magistrate.
Written statement made on oath.
Legal document, used in court applications and proceedings, in which a person swears that certain facts are true.
Written declaration made under oath; a written statement sworn to be true before someone legally authorized to administer an oath

ETYM Latin attestatio: cf. French attestation.
The evidence by which something is attested.
Witnessing; giving evidence; British declaration on oath.

ETYM French certificat, from Late Lat. certificatus made certain, p. p. of certificare. Related to tify.
A document attesting to the truth of certain stated facts; SYN. certification, credential, credentials.