Comments:A common derivative *č`i̯op`è-rV is reflected in Mong. *čöɣe-rü-m and Evk. čupe-r; another suffixed form, *č`i̯op`è-k`V (originally diminutive) may be reconstructed on the basis of Evk. čop-kī and Kor. čabä-gi. The root must have denoted a big water container, perhaps both artificial and natural.