noun
grand-prize diploma; certificate of excellence
A formal certificate awarded for outstanding achievement, often in academic or competition contexts.
彼は全国大会で優等賞状をもらった。
He received a grand-prize diploma at the national competition.
賞状 is a general certificate of commendation, while 優等賞状 specifically denotes a top-level or grand-prize diploma.
Compound of 優等 (excellence, top rank) and 賞状 (certificate, diploma).