Source : WordNet®

application program
     n : a program that gives a computer instructions that provide
         the user with tools to accomplish a task; "he has tried
         several different word processing applications" [syn: {application},
          {applications programme}]

Source : Free On-Line Dictionary of Computing

application program
     
         (Or "application", "app") A
        complete, self-contained program that performs a specific
        function directly for the user.  This is in contrast to system
        software such as the {operating system} {kernel}, {server}
        processes and libraries which exists to support application
        programs.
     
        Editors for various kinds of documents, {spreadsheets}, and
        text formatters are common examples of applications.  Network
        applications include clients such as those for {FTP},
        {electronic mail}, {telnet} and {WWW}.
     
        The term is used fairly loosely, for instance, some might say
        that a client and server together form a distributed
        application, others might argue that editors and compilers
        were not applications but tools for building applications.
     
        One distinction between an application program and the
        operating system is that applications always run in "user
        mode" (or "non-privileged mode"), while operating systems and
        related utilities may run in "supervisor mode" (or "privileged
        mode").
     
        The term may also be used to distinguish programs which
        communicate via a {graphical user interface} from those which
        are executed from the {command line}.
     
        (1994-11-28)