Комментарий: Cf. also Lezg. Khl. sɨw 'summer pasture', Ag. Bursh. su (NB: s:u in the final version of the MSU recordings is obviously a misspelling). Obl. stem *sɨwä-, cf. Lezg. suwa- (Khl. swa-), Tab. siwi-, Ag. suwa-, Rut. sɨwa-. The Ud. form (with suffixed plural marker -ruχ) goes back to *wɨsa - which, in view of the external evidence, seems to be the most archaic variant.
See Лексика 1971, 183; Гигинейшвили 1977, 133; Талибов 1980, 314.