In a physical sense, look at the night sky above a large city from outside the city and notice how it glows. Take that image and apply it to a person, not with light but with their character. (Can also apply to other entities metaphorically perceived as living: dogs, cities, oceans, etc.)
The aura is the elctro-magnetic glow or force field that surrounds every object. In human beings, your aura is actually who you really are! and your body is the shell thats containing it from being released.!
An energy field that surrounds every human being. Each human's aura is a reflection of their personality and emotional state. Some people claim to see auras as glowing fields of light around other people.