ether
(literary or poetic) The substance formerly supposed to fill the upper regions of the atmosphere above the clouds, in particular as a medium breathed by deities.
(by extension) The medium breathed by human beings; the air.
(by extension) The sky, the heavens; the void, nothingness.
(physics, historical) A substance once thought to fill all unoccupied space that allowed electromagnetic waves to pass through it and interact with matter, without exerting any resistance to matter or energy; its existence was disproved by the 1887 Michelson–Morley experiment and the theory of relativity propounded by Albert Einstein (1879–1955).
(colloquial) The atmosphere or space as a medium for broadcasting radio and television signals; also, a notional space through which Internet and other digital communications take place; cyberspace.
(colloquial) A particular quality created by or surrounding an object, person, or place; an atmosphere, an aura.
(organic chemistry) Diethyl ether (C4H10O), an organic compound with a sweet odor used in the past as an anesthetic.
(organic chemistry) Any of a class of organic compounds containing an oxygen atom bonded to two hydrocarbon groups.
Starting fluid.
(slang) To viciously humiliate or insult.