The Collaborative International Dictionary of English v.0.48:

Stereo- \Ste"re*o-\ [Gr. stereo`s solid. See Stare to gaze.]
   A combining form meaning solid, hard, firm, as in
   stereo-chemistry, stereography.
   [1913 Webster]

WordNet (r) 3.0 (2006):

stereo
    adj 1: designating sound transmission from two sources through
           two channels [syn: stereophonic, stereo, two-
           channel]
    n 1: reproducer in which two microphones feed two or more
         loudspeakers to give a three-dimensional effect to the
         sound [syn: stereo, stereophony, stereo system,
         stereophonic system]
    2: two photographs taken from slightly different angles that
       appear three-dimensional when viewed together [syn: stereo,
       stereoscopic picture, stereoscopic photograph]

Moby Thesaurus II by Grady Ward, 1.0:

45 Moby Thesaurus words for "stereo":
   Gramophone, PA, PA system, Victrola, audio sound system,
   audiophile, binaural system, bitch box, bullhorn, cartridge,
   ceramic pickup, changer, crystal pickup,
   derived four-channel system, discrete four-channel system,
   four-channel stereo system, hi-fi, hi-fi fan, high-fidelity,
   intercom, intercommunication system, jukebox, magnetic pickup,
   monaural system, mono, needle, nickelodeon, phonograph,
   photoelectric pickup, pickup, public-address system,
   quadraphonic sound system, radio-phonograph combination,
   record changer, record player, sound reproduction system,
   sound truck, squawk box, stylus, system, tape deck, tape recorder,
   tone arm, transcription turntable, turntable