Question:
This is perhaps the simplest possible question, but what does the # (sharp) in the name of the C# and F# languages mean?
Answer:
There is a theory that C# got this name (initially the language was internally called COOL – C-like Object Oriented Language ) because it would be the evolution of C++, and they continued to play around with incrementing the name of C. So they made the C++++ language , but stacked the two increment operators. Stacked they look like # .
I've seen other theories, like the musical note, but this one seems like it was invented later to have a "better" story.
F# was named to indicate that it is functional C#, after all it uses .NET and follows a similar line to C# despite being heavily inspired by OCaml .
The fact is that this is just an interesting curiosity, the name is what it is.
There's a sensational talk showing the trajectory of .NET/C# and some behind the scenes.