erg (n.2)youdaoicibaDictYouDict[erg 词源字典]
"region of drifting sand dunes," 1875, from French erg (1854), from North African Arabic 'irj, from a Berber word.[erg etymology, erg origin, 英语词源]
marram grassyoudaoicibaDictYouDict
"A coarse European grass of coastal sand dunes, binding the loose sand with its tough rhizomes", Mid 17th century: from Old Norse marálmr, from marr 'sea' + hálmr 'haulm'.