privilege level
In the context of the Intel 80386 processor architecture, the level of authority at which a task executes. There are four available privilege levels; under OS/2 Version 2.0, Level 0 is used for operating system kernel code; Level 1 is not used; Level 2 is used for applications which directly address I/O devices (such as communications applications); Level 3 is used for general application code. In many publications, these protection levels are referred to as "rings", since the protection scheme of the 80386 is often depicted diagrammatically as a series of concentric circles.