C# is a programming language for the .NET framework
C# (pronounced C sharp) is a programming language developed by Microsoft, and specifically designed for the .NET framework. C# incorporates elements from the programming languages Java and C++. C# is an object-oriented programming language. The most important alternative to C# as a programming language to .NET is Visual Basic; there are also other programming languages for .NET that are less important.
The idea behind the development of C# is to create a simpler language that is also suitable for beginners. A further aim for C# is that the programming be platform independent.
C# was influenced by the C++ and Java programming languages
The # could be split into four plus signs (i.e. C++++). C++ and Java influenced C# conceptually, and you can also find similarities to Visual Basic and Delphi. C# is the result of a project that Microsoft began once Sun Microsoft forbad the further development of J++ at the end of the 90s. J++ was Microsoft’s own adaptation of Java, developed by Sun. Developer Anders Hejlsberg is the spiritual father of C#.
You can find more information on C# on Wikipedia: https://en.wikipedia.org/wiki/C_Sharp_(programming_language)