From HomoExcelsior

1. Any of a class of organic compounds in which two hydrocarbon groups are linked by an oxygen atom. 2. ethyl ether 3. The regions of space beyond the earth's atmosphere; the heavens. 4. The element believed in ancient and medieval civilizations to fill all space above the sphere of the moon and to compose the stars and planets. 5. An all-pervading, infinitely elastic, massless medium formerly postulated as the medium of propagation of electromagnetic waves.

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