The Collaborative International Dictionary of English v.0.48:

Intramural \In`tra*mu"ral\, a.
   1. Being within the walls, as of a city.
      [1913 Webster]

   2. Hence: Of or pertaining to those activities occurring
      within a single institution or organization, such as
      intramural sports involving students of a single school;
      an intramural debate within a professional society.
      [PJC]

   3. (Anat. & Med.) Being within the substance of the walls of
      an organ; as, intramural pregnancy.
      [1913 Webster]

WordNet (r) 3.0 (2006):

intramural
    adj 1: carried on within the bounds of an institution or
           community; "most of the students participated actively in
           the college's intramural sports program" [ant:
           extramural]