.NET Standard, .NET Core, and .NET Framework are different implementations of the .NET platform. .NET Standard defines a common language standard and is implemented by both .NET Core and .NET Framework. This allows code written for .NET Standard to run on either .NET Core or .NET Framework. .NET Core is a cross-platform version of .NET that runs on Windows, Linux, and Mac whereas .NET Framework only runs on Windows. The document provides a detailed history of the .NET platform and related technologies from 1991 to present.