ether

ether [ē′thər]

n.

[ME < L aether < Gr aithēr < aithein, to kindle, burn < IE base * aidh- > L aestas, summer, OE ætan, to burn]

1. a substance hypothesized by the ancients as filling all space beyond the sphere of the moon, and making up the stars and planets

2. the upper regions of space; clear sky

3. Rare the air

4. Chem. any of a series of organic compounds having an oxygen atom linking two carbon atoms from two hydrocarbon radicals, generally ROR¹; esp., ethyl ether, a volatile, colorless, highly flammable liquid, H₅C₂OC₂H₅, prepared by the reaction of sulfuric acid and ethyl alcohol and used as an anesthetic and a solvent for resins and fats

5. Physics a hypothetical invisible substance postulated (in older theory) as pervading space and serving as the medium for the transmission of light waves and other forms of radiant energy

etheric [i ther′ik, ithir′ik]

adj.