diploma . ( Of the lat. ) diploma, and this of the Gr. d? p?(µa, of d? p?, double). 1. m. Office, Bull, privilege or other instrument authorized seal and arms of a sovereign, whose original is filed, and, ext., important document. 2. m. title or credential it issued by a corporation, a school, a literary society, etc., to a degree, a prerogative, a prize, etc. diploma shot. 1. m . The issued with the road sign.