Today we're talking physics!
1 : the fifth and highest element in ancient and medieval philosophy that permeates all nature and is the substance composing the celestial bodies
2 : the essence of a thing in its purest and most concentrated form
3 : the most typical example or representative
OK, this is the closest to talking physics you'll get from me. Unless you want to discuss episodes of The Big Bang Theory. Otherwise...yeah. This is it. And remember: when you work this into conversation in the coming week using "quintessentially" is cheating. I don't care if it's the root. Sue me. (Although that would be the definition of a frivolous lawsuit...) See you next week!
PS: Thanks, Merriam-Webster!