Android TV is an operating system designed specifically for SmartTV purposes and is developed by Google. Android TV is basically a smart entertainment platform that comes built into a number of TVs (primarily from Sony, Panasonic, Sharp, etc..) but also in a number of streaming video players like Android TV Boxes and the most popular one, the Nvidia Shield.
To that end, Android TV is considerably similar to iOS or Android. It’s basically an operating system for a TV. It’s capable of supporting various apps, games, and TV shows that you normally navigate with a remote on your TV.