1.Definition: characterized by lightness and insubstantiality; as impalpable or intangible as air

"Physical rather than ethereal forms"

Related Adjective(s):aerial, aeriform, aery, airy

2.Definition: characterized by unusual lightness and delicacy

"This smallest and most ethereal of birds"

Related Adjective(s):gossamer

3.Definition: of heaven or the spirit

"Ethereal melodies"

Related Adjective(s):celestial, supernal

4.Definition: of or containing or dissolved in ether

"Ethereal solution"