An Etymological Dictionary of the German Language/Au

by Friedrich Kluge

Au, Aue, ‘river islet, wet meadow, fertile plan,’ from MidHG. ouwe, f., ‘water, stream, water-land, island, peninsula, meadow-land abounding in water, grassy plain’; OHG. ouwa, from old *aujô- (the presumed Goth. form, comp. OHG.-MidLat. augia). It corresponds to OIc. ey and AS. êg, îg, f., ‘island,’ to which AS. êglond, îglond, E. island, Du. eiland, ‘island,’ are allied; so too Lat. and Teut. Batavia, Scandinavia; Goth. *aujô- (for awjô-, awiâ-) has lost a g (comp. Niere). The theoretical form agwjô-, prop. an adj. used as a subst., ‘the watery place,’ as it were (hence ‘water-land,’ i.e., ‘island’ or ‘meadow’), belongs to Goth. ahwa, f., ‘river,’ which with Lat. aqua is based upon Aryan ákwâ. The names of places ending in a (e.g. Fulda) and ach (e.g. Urach) still preserve the OHG. aha equiv. to the Goth. ahwa. See -a and -ach.