1. An invisible breath, emanation, or radiation.
2. A distinctive but intangible quality that seems to surround a person or thing; atmosphere.
3. In medicine, a sensation, as of a cold breeze or a bright light, that precedes the onset of certain disorders; such as, an epileptic seizure or an attack of migraine.
4. Etymology: from Latin aura "breeze, a breath of air, wind, air" and from Greek aura "breeze, breath".

Epileptic aura (phenomenon perceived only by the patient) characterized by illusions or hallucinations of sound.

The popular breeze.

Cicero's expression for the public's favorite at a particular time; also translated as, "Temporary celebrity".

A type of aura which shows itself in the form of a gustatory hallucination or illusion.

Gustatory aura is associated primarily with paroxysmal neurological disorders; such as, epilepsy and migraine.

A sensory phenomenon that may occur before a migraine.

Visual auras may include flashing lights, geometric patterns, or distorted vision. Some people may have aural (ear) auras that involve hearing sounds (usually buzzing) that are not actually present, olfactory auras that involve smelling odors that are not actually present, or tactile auras that appear as premonitory physical sensations (giving prior warning of disease symptoms).

The auras experienced by migraine sufferers are similar to those associated with epilepsy.

A sudden disagreeable sensation of smell, or odor, preceding or characterizing an epileptic attack