As you've already learned, the .NET Framework is really a cluster of several technologies. These include the following:
The .NET languages
The Common Language Runtime (CLR)
This is the engine that executes all .NET programs and provides automatic services for these applications, such as security checking, memory management, and optimization.
The .NET Framework class library
The class library collects thousands of pieces of prebuilt functionality that you can "snap in" to your applications. These features are sometimes organized into technology sets, such as ADO.NET (the technology for creating database applications) ...