FIFTH ESSENCE: "Quintessential", meaning the most typical or purest example of a category, is derived from the "fifth essence" of the classical elements. Unlike fire, wind, water, and earth, the fifth essence, aether, was the pure, heavenly substance in which the celestial bodies were housed.

Q WITHOUT U: The loanword "qi" refers to a vital force that exists in all living beings. This concept stems from East Asian cultures and proves a useful Scrabble word. The word serves as a Scrabble-legal powerhouse and can also be spelled as "chi" or "ki".