Certificate (noun)

1. A document, typically issued by an official body, attesting to the truth of certain stated facts.
2. A qualification or document confirming the completion of a course or training.
3. An official document issued by a government or other authoritative body, attesting to the fact that certain requirements have been met.

Origin:

Late middle english: from latin certificatus, past participle of certificare "make sure, assure", from certus "certain" + -ficare "make".

Examples:

1. He showed me his certificate of graduation.
2. She has a certificate in accounting.
3. The company provided a certificate of authenticity for the painting.
4. The certificate of marriage was issued by the city.
5. You need a certificate to practice law.