Dictionary.com/ethereal
e·the·re·al Pronunciation Key (-thîr-l)
adj. Characterized by lightness and insubstantiality; intangible.
Highly refined; delicate. Of the celestial spheres; heavenly. Not of this world; spiritual. Chemistry. Of or relating to ether.
[From Latin aetherius, from Greek aitherios, from aithr, upper air.]