Question:
It may be the simplest possible question, but what does the # (sharp) mean in the name of the C# and F# languages?
Answer:
There is a theory that C# got its name (initially the language was called COOL – C-like Object Oriented Language ) because it would be the evolution of C++, and they continued the game of incrementing the name of C. So they made the C++++ language , but they stacked the two increment operators. Stacked they look like # .
I've seen other theories, such as the musical note, but this one seems to have been 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, 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.