The Collaborative International Dictionary of English v.0.48:

Supervision \Su`per*vi"sion\, n.
   The act of overseeing; inspection; superintendence;
   oversight.
   [1913 Webster]

WordNet (r) 3.0 (2006):

supervision
    n 1: management by overseeing the performance or operation of a
         person or group [syn: supervision, supervising,
         superintendence, oversight]