A mobile application or app is a computer program or software application designed to run on a mobile device such as a phone, tablet, or watch. Mobile applications often stand in contrast to desktop applications which are designed to run on desktop computers, and web applications which run in mobile web browsers rather than directly on the mobile device.
An app store (or app marketplace) is a type of digital distribution platform for computer software called applications, often in a mobile context. Apps provide a specific set of functions which, by definition, do not include the running of the computer itself. Complex software designed for use on a personal computer, for example, may have a related app designed for use on a mobile device. Today apps are normally designed to run on a specific operating system—such as the contemporary iOS, macOS, Windows, Linux or Android—but in the past mobile carriers had their own portals for apps and related media content.
A mobile Internet device (MID) is a multimedia capable mobile device providing wireless Internet access. They are designed to provide entertainment, information and location-based services for personal or business use. They allow 2-way communication and real-time sharing. They have been described as filling a niche between smartphones and tablet computers. As all the features of MID started becoming available on smartphones and tablets, the term is now mostly used to refer to both low-end as well as high-end tablets.
A software development kit (SDK) is a collection of software development tools in one installable package. They facilitate the creation of applications by having a compiler, debugger and sometimes a software framework. They are normally specific to a hardware platform and operating system combination. To create applications with advanced functionalities such as advertisements, push notifications, etc; most application software developers use specific software development kits.
A mobile device (or handheld computer) is a computer, small enough to hold and operate in the hand. Mobile devices typically have a flat LCD or OLED screen, a touchscreen interface, and digital or physical buttons. They may also have a physical keyboard. Many such devices can connect to the Internet and connect with other devices such as car entertainment systems or headsets via Wi-Fi, Bluetooth, cellular networks or near field communication.