Carrie, the quintessential single girl, finally ends up married to her true love but doesn't know what to do with him.
-- Ian Caddell, "Morocco brought Sex and the City 2's Sarah Jessica Parker and castmates together", Straight.com
In such a moonlight Gloria's face was of a pervading, reminiscent white, and with a modicum of effort they would slip off the blinders of custom and each would find in the other almost the quintessential romance of the vanished June.
-- F. Scott Fitzgerald, The beautiful and the damned
Quintessential translates from Latin as the "fifth element", quint "fifth" and essentia "essence." The idea of the fifth element stems from Greek and medieval alchemical beliefs in the purest essence of a substance.