noun

1. something that is, or exists; entity
2. that which makes something what it is; intrinsic, fundamental nature or most important quality (of something); essential being
3. 1. a substance that keeps, in concentrated form, the flavor, fragrance, or other properties of the plant, drug, food, etc. from which it is extracted; essential oil
   2. a solution of such a substance or oil in alcohol
   3. a perfume
4. Philos.
   1. the inward nature of anything, underlying its manifestations; true substance
   2. the indispensable conceptual characteristics and relations of anything

Etymology: ME < OFr & L essentia < esse, to be: for IE base see is