Source : Webster's Revised Unabridged Dictionary (1913)

Diploma \Di*plo"ma\, n.; pl. {Diplomas}. [L., fr. Gr. ?, fr. ?
   to double, fr. ? twofold. See {Double}.]
   A letter or writing, usually under seal, conferring some
   privilege, honor, or power; a document bearing record of a
   degree conferred by a literary society or educational
   institution.

Source : WordNet®

diploma
     n : a document certifying the successful completion of a course
         of study [syn: {sheepskin}]