Source : Webster's Revised Unabridged Dictionary (1913)

Postgraduate \Post*grad"u*ate\, a. [Pref. post- + graduate.]
   Of, pertaining to, or designating, the studies pursued after
   graduation, esp., after receiving the bachelor's degree at a
   college; graduate. -- n. A student who pursues such studies.

   Note: Most careful writers consider the word graduate to be
         the proper word to use in this sense.

Source : WordNet®

postgraduate
     adj : of or relating to studies beyond a bachelor's degree;
           "graduate courses" [syn: {graduate(a)}]
     n : a student who continues studies after graduation [syn: {graduate
         student}, {grad student}]