app

app /ap/ n.  Short for `application program', as opposed
   to a systems program.  Apps are what systems vendors are forever
   chasing developers to create for their environments so they can
   sell more boxes.  Hackers tend not to think of the things they
   themselves run as apps; thus, in hacker parlance the term excludes
   compilers, program editors, games, and messaging systems, though a
   user would consider all those to be apps.  (Broadly, an app is
   often a self-contained environment for performing some well-defined
   task such as `word processing'; hackers tend to prefer more
   general-purpose tools.) Oppose {tool}, {operating system}.