Certificate
Part of speech: noun
Definition: A document containing a certified statement. A document evidencing ownership or debt. The information needed in order to verify a positive answer to a problem.
Testimonial
Part of speech: noun
Definition: A statement, especially one given under oath; testimonyA written recommendation of someone's worth or characterA tribute given in appreciation of someone's service etc.A match played in tribute to a particular player (who sometimes receives a proportion of the gate money).