From Proto-Mongolic *sïruxa. Probably related somehow to Proto-Turkic *siāŕ. Compare Dongxiang shoura, Daur shiroo (“grit found in cereal”), Turkish saz (“rush, reed”), Chuvash шур (šur, “bog, swamp”), Hungarian sár (“mud”) (from Turkic), Evenki сиругӣ (sirugī, “sand”).