A program or group of programs designed for end-users. Software can be divided into two general classes systems software and applications software. Systems Software consists of low-level programs, which interact with the computer at the very basic level. This includes Operating Systems, Compilers and Utilities for managing computer resources
In contrast, Application Software (also called end-user programs) includes Database Programs, Word Processors, and Spreadsheets. Figuratively speaking, Application software sits on top of Systems Software because it is unable to run without the Operating System and System Utilities.
For a Software system to be considered as ERP, it must provide an organization with functionality for two or more systems. While some ERP packages exist that only cover two functions for an organization, most ERP systems cover several functions.