online medical dictionary | definition of 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. "Go, heavenly guest, ethereal messenger." (Milton)

2. Consisting of ether; hence, exceedingly light or airy; tenuous; spiritlike; characterised by extreme delicacy, as form, manner, thought, etc. "Vast chain of being, which from God began, Natures ethereal, human, angel, man." (Pope)

3. <chemistry> Pertaining to, derived from, or resembling, ether; as, ethereal salts. Ethereal oil.

<chemistry> A salt of some organic radical as a base; an ester.

(01 Mar 1998)