noun

Roasting marshmallows over an open fire is the quintessence of the camping experience.

“A seven-minute cartoon … containing the quintessence of frustration and despair, Froggy features a construction worker whose sanity begins to unravel when he discovers an ebullient performing frog that he might make a fortune from—if it didn’t turn taciturn and morose the moment anyone else is watching.” — From an article by Nick Pinkerton in The Village Voice , November 20, 2012

Long ago, when people believed that the earth was made up of four elements—earth, air, fire, and water—they thought the stars and planets were made up of yet another element. In the Middle Ages, people called this element by its Medieval Latin name, “quinta essentia,” literally, “fifth essence.” Our forebears believed the quinta essentia was essential to all kinds of matter, and if they could somehow isolate it, it would cure all disease. We have since given up on that idea, but we kept “quintessence,” the offspring of “quinta essentia,” as a word for the purest essence of a thing. Some modern physicists have given “quintessence” a new twist—they use it for a form of so-called “dark energy,” which is believed to make up 70 percent of the universe.

From Merriam-Webster Online at www.Merriam-Webster.com .

Dave