App is a self-contained program or piece of software designed to fulfill a particular purpose; an application, especially as downloaded by a user to a mobile device.
Apps are special software packages that sit on the phone’s memory and carry out specific functions. ”Standalone” apps, such as games, may be used independent of other devices. “Ecosystem-based” apps require integration with content providers (for instance, for receiving health information) or with parts of the health system (such as providing data on medicines in stock).