ethereal

Pertaining to the presupposition of an invisible air-like element permeating all of space, or to the higher regions beyond the earth or beyond the atmosphere.

Near-synonyms: aereous, celestial

ethereal space

Pertaining to the immaterial realm, as symbolically represented by, or (in earlier epochs) conflated with, such atmospheric and extra-atmospheric concepts.

Near-synonyms: celestial, incorporeal, insubstantial, intangible, spiritual, uncorporeal, mystical, otherworldly, transcendental; see also Thesaurus:cosmic

Sure he preſum'd of praiſe, vvho came to ſtock / Th' etherial paſtures vvith ſo fair a flock; / Burniſh'd, and bat'ning on their food, to ſhovv / The diligence of carefull herds belovv.

Consisting of ether; hence, exceedingly light or airy; tenuous; spiritlike; characterized by extreme delicacy, as form, manner, thought, etc.

Vaſt chain of being ! which from God began, / Ethereal Eſſence, Spirit, Subſtance, Man, / Beaſt, Bird, Fiſh, Inſect ! [...]

Strange mystery of our nature, that those in whom genius developes itself in imagination, thus taking its most ethereal form, should yet be the most dependent on the opinions of others!

Ellipsis of ethereal wave (“music genre”).