iOS is a mobile operating system developed by Apple Inc. exclusively for its smartphones. It was unveiled in January 2007 for the first-generation iPhone, launched in June 2007.

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.