open systems

Systems that conform to Open Systems Interconnection or POSIX standards. Unix was the original basis of open systems and most nonproprietary open systems still use this operating system.

The term is also used more loosely to describe any system that can communicate with other systems and to describe other standards, such as MS-DOS and Windows. Open systems were developed partly to make better communication possible, but also to reduce users' dependence on (and lock-in to) suppliers of proprietary systems.