What is the common type system (CTS)?
The common type system (CTS) is a rich type system, built into the common language runtime (CLR) that supports the types and operations found in most of .NET programming languages. The common type system supports the complete implementation of a wide range of programming languages.
What is the Microsoft Intermediate Language (MSIL)?
MSIL is the Machine independent Code into which .NET Framework programs are compiled. It contains instructions for loading, storing, initializing, and calling methods on objects. Combined with metadata and the common type system, MSIL allows for true cross language integration. Prior to execution, MSIL is converted to machine code via CLR’s Just-in-Time (JIT) compiler.