Ethereal

1. Pertaining to the hypothetical upper, purer air, or to the higher regions beyond the earth or beyond the atmosphere; celestial; as, ethereal space; ethereal regions.
2. Consisting of ether; hence, exceedingly light or airy; tenuous; spiritlike; characterized by extreme delicacy, as form, manner, thought, etc.
3. (Chem.) Pertaining to, derived from, or resembling, ether; as, ethereal salts.
Ethereal oil . (Chem.)
See Essential oil, under Essential.
Ethereal oil of wine (Chem.),
a heavy, yellow, oily liquid consisting essentially of etherin, etherol, and ethyl sulphate. It is the oily residuum left after etherification. Called also heavy oil of wine (distinguished from oil of wine, or œnanthic ether).
Ethereal salt (Chem.),
a salt of some organic radical as a base; an ester.