I had a random thought today. I’ve used the word quintessential before… but do I really know what it means? Well, Webster’s is here to help out.

Pronunciation: kwin-'te-s^&n(t)s
Function: noun
Etymology: Middle English, from Middle French quinte essence, from Medieval Latin quinta essentia, literally, fifth essence
1 : the fifth and highest element in ancient and medieval philosophy that permeates all nature and is the substance composing the celestial bodies
2 : the essence of a thing in its purest and most concentrated form
3 : the most typical example or representative

quintessence of calm>
- quin·tes·sen·tial /"kwin-t&-'sen(t)-sh&l/ adjective
- quin·tes·sen·tial·ly adverb

As a side note, from wikipedia: Aether (also spelled ether) is a concept used in ancient and medieval science as a substance. The aether was believed to be the substance which filled the region of the universe above the terrestrial sphere. Aristotle included it as a fifth element distinct from the other four, Air, Earth, Fire, and Water. Aether was also called Quintessence (from quinta essentia, “fifth element”. Quintessence was also supposed to be a definition of pure energy. Its force is imagined to be like a lightning. This element also has the power of life.