well since Murder Inc. dropped the 'Murder' part of it, dont you think that the first thing that would happen is that they run in to legal problems? In my opinion, I believe that 'Ent.' is added at the end of a company or group that is involved in more than one media. These could be the obvious rap groups and/or other music acts, could be involved in film/theatre, you things like that. At least thats what I've seen.