Its pretty much the same thing, but Ford introduced the product as a Moon roof on their 70's cars and soon after other companies started calling the option as a sunroof, more of a generic term. In general a Moonroof is just another form of a sunroof, It doesn't matter if it can open or not. This can be a similar case to Cars that have electronic stability program (ESP) or dynamic stability control (DSC), ESC,etc. Its all the same thing which is "Stability control" as a generic term, but companies call them different things.