quintessence

PIE word *pénkʷe From Middle English, borrowed from Middle French, from Medieval Latin quinta essentia (“fifth essence, aether”). "Essence" in this context is a synonym for "element". In pre-atomic/Aristotelian theory, there are four known elements or essences — Earth, Air, Fire and Water — and a putative fifth element (aether), which is considered to be of exceptional superior quality to the other four basic elements.