A program that is written to run under the Microsoft Windows operating system, also called a "Windows app." All 32-bit Windows applications run in the 32-bit and 64-bit versions of Windows.
web application is a client–server computer program which the client runs in a web browser. Common web applications include webmail, online retail sales, online auctions and many other.
A mobile application, most commonly referred to as an app, is a type of application software designed to run on a mobile device, such as a smartphone or tablet computer.