One of the multiple terms used by movie pirates to describe the source material that was used to make a bootlegged pirate copy, normally distributed in VideoCD, SVCD or DivX format.
Precisely Telesync means a copy which was shot in an empty cinema or from the projection booth with a professional camera, directly connected to the sound source.
Other bootleg version methods include Telecine, Screener, Cam and DVD-Rip.
Recently however, there have been movements to ban camming from theaters, and to put the offenders in jail or leave them with large fines.
In the news:
New York wants stricter punishments for film pirates (6 May 2008)
Police arrest and charge "maVen" of piracy scene (6 December 2007)
MPAA want to make movie camming a criminal offense in UK (7 September 2007)