.NET Framework is a software framework developed by Microsoft, includes a large class library and provides language interoperability across several programming languages. Code written using .NET Framework is called “managed code”. FCL and CLR together constitute the .NET Framework.
.NET Core is a free and open-source, managed computer software framework for Windows, Linux, and macOS operating systems. It is a cross-platform successor to .NET Framework. The project is primarily developed by Microsoft and released under the MIT License.