tvOS (formerly Apple TV Software) is an operating system developed by Apple Inc. for the 2nd generation and later Apple TV digital media player. It is based on the iOS operating system and has many similar frameworks, technologies, and concepts.
The Apple TV Software for the 2nd and 3rd generation Apple TV has several built-in applications, but does not support third-party applications.
The 4th generation Apple TV, with support for third-party software via an App Store, was rumored prior to the Apple September 2015 event held on September 9, 2015.
On September 9, 2015 at the Apple September 2015 event, Apple announced the 4th generation Apple TV, with support for third-party applications; Apple changed the name of the operating system to 'tvOS', adopting the nomenclature that they were using for their other operating systems, iOS, watchOS, and macOS.