The Collaborative International Dictionary of English v.0.48:

Campus \Cam"pus\, n. [L., a field.]
   1. The principal grounds of a college or school, between the
      buildings or within the main inclosure; as, the college
      campus.
      [1913 Webster]

   2. a college or university.
      [PJC]

   3. a division of a university with its own buildings and a
      separate faculty, especially one separated geographically
      from other divisiona, but sharing top administration with
      other units of the university; as, the Newark campus of
      Rutgers.
      [PJC]

   4. higher education considered as a whole; as, the financial
      effects of research cutbacks on the campus.
      [PJC]

   5. a business site with pleasant landscaping; as, the Squibb
      research campus at Princeton.
      [PJC]

WordNet (r) 3.0 (2006):

campus
    n 1: a field on which the buildings of a university are situated