concFrom Grk aithḗr ‘upper air; bright, purer air; the sky’. – »In ancient cosmology, the element that filled all space beyond the sphere of the moon, constituting the substance of the stars and planets. Conceived of as a purer form of fire or air, or as a fifth element. From 17c.-19c., it was the scientific word for an assumed ‘frame of reference’ for forces in the universe, perhaps without material properties. The concept was shaken by the Michelson-Morley experiment (1887) and discarded after the Theory of Relativity won acceptance, but before it went it gave rise to the colloquial use of ether for ‘the radio’ (1899). – The name also was bestowed c.1730 (Frobenius; in English by 1757) on a volatile chemical compound known since 14c. for its lightness and lack of color (its anesthetic properties weren’t fully established until 1842).« – etymonline, s.v. »ether«.