Emily Dickinson Lexicon

QUIN-TES'SENCE, n. [L. quinta essentia, fifth essence.]

1. In alchimy, the fifth or last and highest essence of power in a natural body. Hence,
2. 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 Ethereal, first of things, quintessence pure, / Sprung from the deep. – Milton.
3. In chimistry, a preparation consisting of a vegetable essential oil dissolved in spirit of wine.
4. The pure essential part of a thing. [I have followed Bailey and Ash and our general usage in the accentuation of this word. Jameson has done the same. The accent on the first syllable is very unnatural.]