e'ther, n. [L. æther; Gr. aithê; the upper, purer air, ether, from aiethien, to kindle, burn.]

1. In astronomy and physics, a hypothetical medium of extreme tenuity and elasticity supposed to be diffused throughout all space (as well as among the molecules of which solid bodies are composed), and to be the medium for the transmission of light and heat.

There are fields of light and liquid ether flow.
-- Dryden.