Great questions, but did you mean "sketch" instead of "script"? I think that may derive from the artsy nature of Wiring, from which Arduino is descended. There's another one. "Wiring" is probably the last name I would have chosen, unless it was Processing. But it is what it is. I really try not to think about these things, don't get me started 
Please feel free to use terms like "source code" and "program" etc. etc. XD