FCL
From RemObjects Software
The Framework Class Library is a set of types included with the .NET framework that are the standard set of types required to run .NET applications.
These types are spread over several assemblies and in different namespaces. The most important namespace is the "System" namespace, which contains the classes for base types like Int32, Int64, Double, String and Char. The System.Collections and System.Collections.Generic namespaces contain structures like lists and dictionaries, essential for application development.
Other namespaces include the System.IO for reading and writing to files and other streams, System.Net for socket support. System.Reflection for reading and generating assemblies on the fly.
