When a computer programme is written to perform a specific task other than one related to the operation of the computer itself, it is known as an application programme (app or application for short). Application programmes are typically designed to be used by end-users and are therefore referred to as "apps." A few examples of such software are word processors, media players, and accountancy packages. The collective term refers to all of the applications as a grouping of related applications. System software, which is concerned with the functioning of the computer, and utility software are the other two major types of software ("utilities").
Applications may be included with a computer and its operating system software, or they may be released independently. They may be developed as proprietary, open-source, or project code, among other formats. Mobile applications, such as those for phones, are sometimes referred to as "apps."
In information technology, an application (app), application programme, or application software is a computer programme that is meant to assist humans in the performance of a certain task or activity. An application may alter text, numbers, audio, visuals, and a mix of these components, depending on the activity for which it was created and the platform on which it runs. The majority of application packages are focused on a particular activity, such as word processing; but, others, referred to as integrated software, combine a number of different programmes.
Computer systems are tailored to fit the special requirements of users who write their own software. Spreadsheet templates, word processing macros, scientific simulations, music, graphics, and animation scripts are all examples of user-written software. E-mail filters, for example, are considered to be a kind of application software. Users develop this software on their own and often underestimate its significance.
It should be noted, however, that the distinction between system software such as operating systems and application software isn't always clear, and it is sometimes the source of debate. The question of whether Microsoft's Internet Explorer web browser was considered part of its Windows operating system or a separate piece of application software was one of the central issues in the United States v. Microsoft Corp. antitrust trial, for example. In a similar vein, the GNU/Linux name debate is partly a result of differing viewpoints on the connection between the Linux kernel and the operating systems that are built on top of the Linux kernel, as an example. It is possible that the application software and the operating system software are indistinguishable to the user in certain kinds of embedded systems, such as software used to manage a VCR, DVD player, or microwave oven, for example. Some apps that may be present on some computers in big companies may be excluded from the above criteria due to their complexity. See Application Portfolio Management for a different definition of an application.