Viacom Inc. , short for "Video & Audio Communications", is an American global mass media company with interests primarily in, but not limited to, cinema and cable television. As of 2010, it is the world's fourth-largest media conglomerate, behind The Walt Disney Company, Time Warner and News Corporation. Viacom is owned in majority by National Amusements, Inc. , a privately owned theater company based in Dedham, Massachusetts, USA.