[Noun] Official papers or documents which prove that something is true. Example: The asylum seekers were asked to bring their credentials to the police station to be checked.
Found on http://www.bbc.co.uk/skillswise/glossary/
Instruments which an ambassador, envoy, or other diplomatic agent receives from their own government authorizing them to appear in their diplomatic character and defining their powers. The... Found on http://www.encyclo.co.uk/local/20688