How about this definition? Native means that it doesn't work equally well on all platforms but is clearly designed in the context of one single specific platfor

How about this definition? Native means that it doesn't work equally well on all platforms but is clearly designed in the context of one single specific platform (although that platform could arguably be layered on top of another platform). If I were a native German, I wouldn't work equally well if suddenly dropped in the middle of France – I would be confused about the language, the geography, the culture, etc. So if someone designs, for example, a window system with support for sound and vector graphics (these being the defining features of the system), a native application for this system would be one that uses the characteristic built-in features of the system to create windows, play sound and draw vector graphics, the expression of the application being shaped by the nuances of how these things work on this particular system. A non-native application would be one that abstracts windows, sound and graphics to work equally well on all kinds of systems and hides the peculiarities (or advantages) of this specific system.