Noah Webster's Dictionary 1. (a.) Giving a title or claim to credit or confidence; accrediting. 2. (n.) That which gives a title to credit or confidence. 3. (n.) Testimonials showing that a person is entitled to credit, or has right to exercise official power, as the letters given by a government to an ambassador or envoy, or a certificate that one is a duly elected delegate.

Multi-Version Concordance Credential (1 Occurrence) 2 Thessalonians 3:17 I Paul add the greeting with my own hand, which is the credential in every letter of mine. (WEY)