Why do we call it 'white wine'?

A non-committal please-everybody glass of rose.

A non-committal please-everybody glass of rose.

White wine, so called, is usually a shade of yellow. The yellower it is, in general, the more likely it tastes like Chardonnay (the capital is kosher: that's the official region) and the less likely it is to be like Pinot Grigio (Pinot Gris in France) or Spanish Albariño, or other mineraly wines. 

But again the question is: why are yellow(ish) wines called 'white'? And why, given that they come from green grapes and that grape skins are known to colour wine, are they not in the least bit green?