Metro has been one of the popular term which associated with Windows Phone and Windows 8 since introduction of Windows Phne and early development of Windows 8 to indicate the new user interface (UI) design and apps specifically built using WinRT (Windows Runtime) programming interface or WinPRT (Windows Phone Runtime) that run on the new environment.

In the case of Windows 8, the term Metro has often used to differentiate the traditional desktop environment for Windows operating system from the new touch-optimized user interface that is introduced in Windows 8, and is featured prominently through Start screen that replaced the classic Start button.

According to Tom Warren, the “Metro” is officially replaced by simply “Windows 8 Modern UI” to describe the new UI and apps system.

Windows 8

Accordingly, the phrases “Metro style app” or “Metro app” are replaced by “Windows 8 Modern UI style app” or simply “Windows 8 Modern UI app”; while other Metro references such as “Metro UI”, “Metro design” and “Metro style” been changed into “Windows 8 Modern UI”, “Windows 8 Modern UI design”, and “Windows 8 Modern UI style” respectively.

The change of name from Metro to Modern is mainly due to a trademark infringement with Metro Group, a diversified retailer based in Düsseldorf, Germany.

Microsoft has confirmed the depreciation of the Metro term, and claimed that the Metro term was always just a codename. Although Microsoft has used the Metro term extensively in the past, nonetheless, the recent blog posts, events description and other publishing by Microsoft have started to use Modern UI-style applications to refer to what previously known as Metro-style applications.

Windows 8 will go on sale on October 26th, 2012, but will released more than two months ahead on August 15th, 2012 to MSDN and TechNet subscribers.