In alchimy, the fifth or last and highest essence of power in a natural body. Hence,

An extract from any thing, containing its virtues or most essential part in a small quantity: . Let there be light, said God; and forthwith light etherial, first of things, quintessence pure, sprung from the deep.

In chimistry, a preparation consisting of the essential oil of a vegetable substance, mixed and incorporated with spirit of wine.

The pure essential part of a thing.