I'm a bit late on this one, but since it is a really interesting case I'll add my pinch of salt.... That final 's' almost certainly shows a germanic origin, where the root of the word is not. In fact the old english word 'mylen' is directly copied from the latin word 'molinum', and is one of the handful of rare words to have done so. Other 'latin' words were re-imported via french after 1066. Both words in fact mean 'grinding stone' rather than mill - perhaps there is a specialist out there who could tell us where and when the first water/windmills appeared? The latin words molina/molinum only appear after the christianisation of Rome, so it may be debatable as to who copied whom - does the word have celtic origins? I would be very happy if someone could give more info on this point. Geoff