essence

(ĕsˈəns)

1. The intrinsic or indispensable properties that serve to characterize or identify something.
2. The most important ingredient; the crucial element.
3. The inherent, unchanging nature of a thing or class of things.
4. a. An extract that has the fundamental properties of a substance in concentrated form.
   b. Such an extract in a solution of alcohol.
   c. A perfume or scent.
5. One that has or shows an abundance of a quality as if highly concentrated: a neighbor who is the essence of hospitality.
6. Something that exists, especially a spiritual or incorporeal entity.