Definitions of ethereal:

• adjective:   of or containing or dissolved in ether

  Example: "Ethereal solution"

• adjective:   characterized by unusual lightness and delicacy

  Example: "This smallest and most ethereal of birds"

• adjective:   of heaven or the spirit

  Example: "Ethereal melodies"

• adjective:   characterized by lightness and insubstantiality; as impalpable or intangible as air

  Example: "Physical rather than ethereal forms"