In computing “app” is an abbreviation of application – a piece of software that runs on a computer, a mobile device or other platform (for example, an iPhone or Facebook.) App is really a generic term for any standalone bit of software.

(Of course it’s a pretty new word, so now people are fighting over it. Apple is suing Amazon in a bid to stop the online retail giant from using the name Appstore, which will offer downloadable applications for Google’s Android operating system.. Apple, which makes iPhones and iPads, claims that the name is deliberately similar to its own App Store. “It will confuse and mislead customers,” said Apple spokeswoman Kristin Huguet. I think I’m going to put a claim on the term “shoe store”. I mean enough shoe salesmen target the forum, I think I have a very good case.)