From Wiktionary, the free dictionary
Sino-Vietnamese word from 素娥, composed of 素 (“clean, white”) and 娥 (“fairy”).
tố nga
- (rare) Hằng Nga
- (archaic, literary) pretty girl
1820, Nguyễn Du (阮攸), Đoạn trường tân thanh (Truyện Kiều)[1], published 1866, lines 15–16:頭𢚸𠄩妸素娥
翠翹姉㛪翠雲- The first-borns were two beautiful daughters.
Thúy Kiều the eldest, Thúy Vân the younger.