ethereal (adj.)youdaoicibaDictYouDict[ethereal 词源字典]
formerly also etherial, 1510s, "of the highest regions of the atmosphere," from ether + -ial; extended sense of "light, airy" is from 1590s. Figurative meaning "spirit-like, immaterial" is from 1640s. Related: Ethereally.[ethereal etymology, ethereal origin, 英语词源]