The term “app” is short for “application,” which is how people interact with computers and mobile devices. So “app” is a computer program for interacting with people. Often this is called “software” as it is the set of instructions that control how the hardware, or physical device, behaves. Spreadsheets, word processing programs, browsers and email clients are all “applications.” On your mobile device, the various icons on your home screen that allow you to interact on your phone are all “apps.” Often “app” refers to an application on a mobile device, but in general, it is just software, or a computer program, designed for human interaction.