Quintessence is the most important part of anything. It can also mean the pure essence of a substance. The word comes from quinta essentia, which means fifth essence. The Greeks had four basic elements: water, air, earth and fire. Pythagoreans then added a fifth element to that, called nether. After that people started considering the fifth element, or fifth essence, the most important one.
His most famous advertising campaign, for Arrow shirts and collars, which is still cited as a symbol of the flapper era, was the quintessence of stylishness and put the company on the fashion map. (NY Times)
Those of us who fight for the integrity of our generation’s music point to “political” — as opposed to “party” and “gangsta” — rap as an example of its potential. Its quintessence was epitomized in the late 1980s during hip-hop’s “stop the violence movement.” (USA Today)