Dictionary:

app

  (ăp)

A computer application.

[Short for APPLICATION.]

(1) A set of files that make up software for the user. The terms "application" and "application program" are synonymous; however, there could be a technical difference if both terms are used in the same conversation. In that case, "application" would refer to the complete set of files that have to be installed (executables, configuration files, ancillary data files, etc.), whereas the "application program" would refer to just one executable file. See application program.

(2) A specific use of the computer, such as for payroll, inventory and billing. For a list of major application software categories, see application software.

Appreciation (in appraisal terminology).

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.) See killer app; oppose tool, operating system.