Ethereal

Adjective:
1. Characterized by lightness and insubstantiality; as impalpable or intangible as air
2. Of or containing or dissolved in ether
3. Of heaven or the spirit
4. Characterized by unusual lightness and delicacy

Usage:
1. Physical rather than ethereal forms
2. ethereal solution
3. ethereal melodies
4. this smallest and most ethereal of birds

Synonyms:
1. Aerial
2. Aeriform
3. Aery
4. Airy
5. Celestial
6. Gossamer
7. Supernal