Given that this is a programmer's web site, perhaps it is interesting to list the "real names", the names that the Microsoft programmers used when they worked on the projects. These names tend to show up, like archeological records, in the source code for the CLR (Rotor), SDK header files and the Reference Source.
C# started out as COOL (C-like Object Oriented Language). The Rotor makefiles show that early C# code might have been written in files with the .cool filename extension. However, there are also several places where it is named COOLC.
The CLR had several names. It started out as a project inside the group that worked on Windows 2000's COM+, there are many references to "ComPlus" in the CLR source code. The exception code for a managed exception is 0xe0434f4e, 0xe0 + "COM"+1. In the WinError.h file, CLR error codes use "URT", "Universal Run Time". The contraction "Cor" appears in many places in the hosting interfaces, "COM Object Runtime". CLR source code very commonly uses the EE acronym, distinct from COR, short for Execution Engine and part of the changes in the CLR code base to get it to execute managed code.
Internal project names I've seen:
- Rainier: Visual Studio 2002
- Everett: Visual Studio 2003
- Whidbey: Visual Studio 2005
- Orcas: Visual Studio 2008
- Hawaii: Visual Studio 2010 (very early)
- Rotor: Shared Source version of the CLR
- Avalon: WPF
- Indigo: WCF
- Yukon: SQL Server 2005
- Katmai: SQL Server 2008
- Strike: a custom debugger extension used to debug the first version of the CLR, evolved into SOS (Son of Strike).