Source : Webster's Revised Unabridged Dictionary (1913)

Ethereous \E*the"re*ous\, a. [L. aethereus, Gr. ? See {Ether}.]
   1. Formed of ether; ethereal. [Obs.]

            This ethereous mold whereon we stand. --Milton.

   2. (Chem.) Pertaining to, or resembling, ether.

   {Ethereous oil}. See {Ethereal oil}, under {Ethereal}.