Cool word for the day - Quintessence

I saw the word "quintessence" in a forum the other day... It was used completely incorrectly there - they meant coincidence but said their spell-checker lead them to quintessence instead - but nevertheless I thought "what a cool word" when I saw it.

Here's dictonary.com on on quintessence. there are lots of definitions given, but the common theme is one of "the purest and most concentrated essence of something."

Historically it seems to have roots as the 5th and essential element that permeates everything - after earth, air, fire, and water.