Credential

Webster's Dictionary of the English Language

·noun That which gives a title to credit or confidence.

II. Credential ·adj Giving a title or claim to credit or confidence; accrediting.

III. Credential ·noun 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.