An application program (sometimes shortened to application ) is any program designed to perform a specific function directly for the user or, in some cases, for another application program. Examples of application programs include word processors; database programs; Web browsers; development tools; drawing, paint, and image editing programs; and communication programs. Application programs use the services of the computer's operating system and other supporting programs. The formal requests for services and means of communicating with other programs that a programmer uses in writing an application program is called the application program interface (API).
A lot of times you don’t need to use an app as a user. You’re better off going to the site’s main website. An app that shows you a stripped-down version of a site in the form of an app can be downright annoying. One of the things I hated about my Android tablet was the way it defaulted to a Twitter app and would not even let me visit the full site. But I liked to use the full site. I hated being forced to use a dweezy app that hid half the Twitter features. Plus, I know the layout of the full Twitter site and didn’t have to guess where things were, as I did with the app.