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.
Apps were originally
intended for productivity assistance such as email, calendar, and contact
databases, but the public demand for apps caused rapid expansion into other
areas such as mobile games, factory automation, GPS and location-based services,
order-tracking, and ticket purchases, so that there are now millions of apps
available. Many apps require Internet access. Apps are generally downloaded from
app stores, which are a type of digital distribution platforms. (資料來源 )