I don’t know if Google TV is just a launcher, but I can answer the question "what is a launcher?"
On Android systems, a launcher is the home screen plus a little more. iPhone doesn’t have this concept as there's only one "launcher": the home screen. On android, however, you can install apps to radically change your home screen layout. Some are terminals, some are just A-Z lists of your apps, etc. A launcher on Android TV would be more significant because it would probably include movies, shows, and music instead of just apps.
On Android systems, a launcher is the home screen plus a little more. iPhone doesn’t have this concept as there's only one "launcher": the home screen. On android, however, you can install apps to radically change your home screen layout. Some are terminals, some are just A-Z lists of your apps, etc. A launcher on Android TV would be more significant because it would probably include movies, shows, and music instead of just apps.