.NET was always a clusterfuck of naming, as in the early 2000s Microsoft was slapping the .NET label everywhere. .NET Passport (now known as Microsoft accounts), .NET My Services, Visual Studio .NET (which was the same as regular VS, just with support for building C# and VB.NET apps added), .NET Server 2003 (Windows Server 2003), et weary cetera.

In this respect, as in many others related to .NET, Microsoft was inspired by Java. In the late 90s, Java wasn't just a language, it was a VM, runtime environment, enterprise platform (Java EE, now Jakarta EE), smartcard technology, remoting protocol, operating system, desktop environment, floor wax, dessert topping...