quintessence

n. [ F., fr. L. quinta essentia fifth essence. See Quint, and Essence. ] 1. The fifth or last and highest essence or power in a natural body. See Ferment oils, under Ferment. [ Obs. ] [ 1913 Webster ]

☞ The ancient Greeks recognized four elements, fire, air, water, and earth. The Pythagoreans added a fifth and called it nether, the fifth essence, which they said flew upward at creation and out of it the stars were made. The alchemists sometimes considered alcohol, or the ferment oils, as the fifth essence. [ 1913 Webster ]

2. Hence: An extract from anything, containing its rarest virtue, or most subtle and essential constituent in a small quantity; pure or concentrated essence. [ 1913 Webster ]

Let there be light, said God; and forthwith light
Ethereal, first of things, quintessence pure,
Sprung from the deep. Milton. [ 1913 Webster ]

3. The most characteristic form or most perfect example of some type of object. [ PJC ]