What Does App Mean?
An app is computer software, or a program, most commonly a small, specific one used for mobile devices. The term app originally referred to any mobile or desktop application, but as more app stores have emerged to sell mobile apps to smartphone and tablet users, the term has evolved to refer to small programs that can be downloaded and installed all at once.
There are thousands of apps designed to run on today's smartphones and tablets. Some apps can be downloaded for free, while others must be purchased from an app store.
Techopedia Explains App
An app is just software. Originally software that you installed on a computer as a program was labelled as an application - or the shortened name of app. However, the common usage of "app" versus "application" now generally refers to the distribution through app stores where the download and installation happen with a single action. While you were always able to download software, this method of distribution is a new development. Apple's App Store and Google's Android Market are two examples of popular app stores.
The downside of apps installed this way is the app store all have the ability to remove or discontinue the use of the software remotely. The user has no option and must just suffer the loss of data.
According to a 2010 study by the Pew Institute, one in four adults in the United States was using mobile apps. Apps were most commonly used to take pictures, send or receive text messages, access the Internet or play games. The apps market is considered a major and growing part of the smartphone market. Apps are easy and inexpensive to purchase and can be installed and removed from a device almost instantly without affecting the device's systems or other apps. Finally, the vast majority of apps are for mobile devices, but an app can be for a non-mobile device as well.