Microsoft Intermediate Language (MSIL) is a language used as the output of a number of compilers(C#, VB, .Net, and so forth). The ILDasm (Intermediate Language Disassembler) program that ships with the .Net Framework SDK allows the user to see MSIL code in human readable format.
When compiling to manage code, the compiler translates your source code into Microsoft intermediate language (MSIL), which is the CPU independent set of instructions that can be efficiently converted into native code. MSIL includes instruction for loading, storing, initializing, and calling method on objects, as well as instructions for arithmetic and logical operations, control flow, direct memory access, exception handling, and other operations. Before code can be run, MSIL must be converted to CPU- specific code, usually be JIT – compiled and run on any supported architecture.