n. Originally, a letter or other composition written on paper or parchment and folded.n. Hence Any letter, literary muniment, or public document. See diplomatics.n. In modern use, a letter or writing, usually under seal and signed by competent authority, conferring some honor, privilege, or power, as that given by a college in evidence of a degree, or authorizing a physician to practise his profession, and the like.To furnish with a diploma; certify by a diploma.