Ethereal medium

(Physics) the ether.

See also: Medium

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
For now, Selby Gallery's exhibition will stir the public's interest and enthusiasm for this ethereal medium as they witness first-hand examples of an art that is evocative and, for collectors, addictive enough to set hearts afire.
A vacuum would certainly prohibit further ascent, but Poe argued in favor of "an extremely rare ethereal medium" pervading the interplanetary realm.