Essence is a polysemous word that refers to the intrinsic nature or indispensable quality of something that determines its character.
In philosophy, essence is contrasted with existence - the former refers to "what a thing is", while the latter refers to "that a thing is".
The term "essence" also refers to:
1. A concentrated liquid containing the characteristic fragrance of a plant
2. The most important ingredient or element of something
3. In philosophy, the set of attributes that make an entity what it fundamentally is