Definition: Abbreviated as OS, it is a usually large software program that controls and manages the hardware and other software on a computer.
The most popular operating systems today include versions of Microsoft Windows, Apple's Mac OS, and flavors of the open source operating system Linux.
Also Known As: OS
Examples: "I have a number of friends that use different versions of the Linux operating system but I've always been a huge fan of Microsoft Windows. In fact, I my last upgrade was from Microsoft Windows XP to Microsoft Windows Vista."
