What is the difference between Func<string,string> and delegate?

I see delegates in two forms:

A. Func<string, string> convertMethod = lambda 

B. public delegate string convertMethod(string value);

I'm uncertain of what actually the difference between these two are. Are they both delegates? I believe the first one would use a lambda and the second would have to have a method to actually perform the work. I may be confused too.