Comments:A Turk.-Mong. isogloss. Phonetically a good match would be Jpn. *úrúsí 'lacquer' ( < *'liquid'?), but semantics raises doubts. Poppe 102 compares *urus- with Evk. urigden 'backwater' - the same comparison see in ОСНЯ 1, 240-241. Cf. also Yak. ürex, Dolg. ürek 'river' (Stachowski 253) - suggesting that *-si might be an original suffix.
