The Common Type System (CTS)

.NET Framework defines a Common Type System (CTS), like CLS, CTS is also a set of standards. CTS defines the basic data types that IL understands. So each .NET language should map its data types to these CTS data types. This makes it possible for the two languages to communicate each other by passing/receiving parameters to and from each other.

Example: CTS defines a type, Int32, an integral data type of 32 bits, which is mapped by C# through int, VB.NET through Integer data type.