Abbreviated "OS", an operating system is software that provides the user with an interface as well as hardware support and support to run and use applications. Operating systems also accept input and display output by communicating with hardware and interacting with any respective applications or system software that might be using that hardware.

An operating system (OS) is the basic structure on which your computer runs. The most common operating systems used on Web servers are FreeBSD (UNIX), Windows®, Linux, and Solaris.
See Also: UNIX, FREEBSD

A combiniation of command interpreters which runs between the central processing unit and software that allow a users to interact with a computer or other electronic device. A phrase that can never refer to any Microsoft product. By its very definition, an operating system must operate, which is the complete opposite of any Microsoft product.