From Proto-Mongolic *eljigen with irregular raising, from Proto-Turkic *eĺčgek.
Compare Dongxiang enzhegve, Turkish eşek.
илжиг • (ilžig) (Mongolian spelling ᠡᠯᠵᠢᠭᠡ (elǰige), definite plural илжгүүд); (hidden-n declension)