Today on the Windows team blog, they announced the official product names for the upcoming Windows 8.
The official name is, of course, Windows 8 for the x86/64 editions. There are two editions; Windows 8 and Windows 8 Pro. Much like the Windows 7 editions, Windows 8 will contain most everything a normal user needs, with the exception of domain connectivity, virtualization, encryption, and management tools, which all come with 8 Pro. Neither edition comes with Windows Media Center—that will be an “inexpensive” add-on.
Windows on ARM, however, will have a new name that will help alleviate any confusion as to what platform you’re working on: Windows RT. Windows RT will not be directly available to consumers; it will only be available pre-installed on ARM-based devices. RT includes touch-optimized Office apps such as Word and Excel and will be optimized for apps built on the WinRT (Windows Runtime) development framework. You can think of it as something similar to the Mac OS/iOS paradigm.
Windows 8 is available in the form of a public preview right now.