n. The fifth essence, or fifth body, not composed of earth, water, fire, or air; the substance of the heavenly bodies, according to Aristotle, who seems in this matter to follow Pythagorean doctrine.n. Hence An extract from anything, containing its virtues or most essential part in a small quantity; pure and concentrated essence; the best and purest part of a thing; in old chemistry, an alcoholic tincture or essence often made by digestion at common temperatures or in the sun's heat, and always at a gentle heat.To extract as a quintessence; reduce to a quintessence.