Lat. auster ‘south wind; south’, austrālis ‘southern’: aurōra, etc., is a well established etymology, but not sufficiently explained. Both groups of words may be referred to a base *awes- or perhaps rather *ēwes- (with a- from ǝ), with the primary meaning ‘wave, roll, rise’, descriptive of fire and water. Hence *austro- was used both of the east, orient, in reference to the rising of the sun, and of the south, or rather of the south wind, as the rain-bearer, storm-bringer, thawer. For Lat. auster is described as fulmine pollens (Lucr. 5. 744), turbidus (Hor. Od. 3. 3. 4), nullius (Prop. 2. 15, 56), humidus (Virg., G 1. 462), pluvius (Ovid, M 1. 66), and also as frigidus, hibernus, validus, vehemens. We may therefore compare Skt. oṣárn ‘geschwind; sogleich’, Swed. yster ‘sehr lebhaft, unbändig’, ORG ustar ‘gierig’, ustr ‘Fleiss’; Norw. ӯr ‘ausgelassen’, Swiss ūr, ūrig ‘stürmisch (von Wetter), wild, zornig’, Bav. eurisch ‘mürrisch’ (or these with IE r); Norw. ӯsja ‘swarm out, of small animals’, usta ‘stöbern’ (of dust or rain), usle ‘coaldust’, ON usti ‘glowing ashes’, ysja ‘fire’, Lat. ūro, Skt. uṣmā 'Hitze, Glut, Dampf, etc.; vāsa-h 'Wolgeruch', Swed. ōs 'Dunst, Geruch,' OE wōs 'moisture, juice', MLG wōs ‘Absud, Brühe, Most’, wasem ‘Wasserdampf, Dunst’, OHG wasulun ‘pluviis’, Norw. vaslast ‘nass werden, fliessen’.