The Collaborative International Dictionary of English v.0.48:

broadcasting \broad"cast`ing\ n.
   the medium that disseminates via telecommunications; radio
   and television.

   Syn: broadcast media.
        [WordNet 1.5]

   2. taking part in a radio or tv program.
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

broadcasting
    n 1: a medium that disseminates via telecommunications [syn:
         broadcast medium, broadcasting]
    2: taking part in a radio or tv program