App Store n. An App Store, sometimes also known as a Software Center or Software Manager, is a graphical user interface which allows the user to conveniently download and install new applications onto their computer or mobile device. App Stores can be very convenient but are often proprietary and may enable a particular company to control and censor what types of application non-technical users may run on their systems - typically in accordance with an American west coast morality. App stores have sometimes been described as a type of MITM attack on software distribution, allowing companies to insert themselves as rent-seeking trolls on a virtual toll bridge between the users and producers of software.