(1) Software that is used for business or entertainment purposes. An "application" or "application program" refers to virtually any type of program from spreadsheets such as Excel to media players such as iTunes. However, the term specifically excludes essential control software such as the operating system (see system software).

One or Many Files
An application can be made up of a single executable file or hundreds of files, which includes additional software modules, configuration files and ancillary data files. See application program and application software.

(2) A functional category such as payroll, inventory and billing, or a business category such as manufacturing, banking and retail.