What is C#? C# is an object-oriented programming language designed by Microsoft, based on Java and C++ and designed to be portable (although it's actual portability was limited until recently). It's one of the primary languages used on the .NET framework along with C/C++ as well as the primary scripting language in Unity, powered by Mono.
Mono, an open source implementation of the .NET libraries, allows C# programs to run on platforms other than Microsoft's own. The aquisition of Xamarin (the company who maintained Mono at the time) by Microsoft in March 2016 led to the complete relicensing of Mono to a more permissive license, thus opening C# to a wider range of applications in an even wider range of platforms.
