·adj Pertaining to, derived from, or resembling, ether; as, ethereal salts.
II. Ethereal ·adj Consisting of ether; hence, exceedingly light or airy; tenuous; spiritlike; characterized by extreme delicacy, as form, manner, thought, ·etc.
III. Ethereal ·adj 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.