noun (n)

• a sensation (as of a cold breeze or bright light) that precedes the onset of certain disorders such as a migraine attack or epileptic seizure(noun.state)

  source: wordnet30
• an indication of radiant light drawn around the head of a saint(noun.attribute)

  Synonym:
  aureole, gloriole, glory, halo, nimbus
  

  source: wordnet30
• a distinctive but intangible quality surrounding a person or thing(noun.attribute)

  Example:
  The place had an aura of romance.
  

  Synonym:
  air, atmosphere
  

  source: wordnet30
• Any subtile, invisible emanation, effluvium, or exhalation from a substance, as the aroma of flowers, the odor of the blood, a supposed fertilizing emanation from the pollen of flowers, etc.(noun)

  source: webster1913