As you’ve seen, all .NET languages compile code targeting IL as the destination code format. Today’s processors do not know how to execute code written in this format, so something needs to happen to turn IL code into instructions the target processor can deal with. The runtime service that’s responsible for making the mapping between IL code and native processor instructions is called the Just-in-Time compiler, often abbreviated as JIT and referred to as “the jitter.”
Note: Restricting Target Execution Platforms
Although IL code is machine-independent, the .NET language compilers provide a
/platform switch to request JIT compilation to a particular assembly language. Although the portability across machine architectures is a ...