Quiddity

WORD OF THE DAY

quiddity / noun / KWID-uh-tee

Definition
1a: whatever makes something the type that it is
1b: essence
2a : a trifling point
2b: quibble
2c: an unusual personal opinion or habit
2d: eccentricity

Examples
"The elegant, punky, petroleum-like smokiness that imbues every good mezcal, and which is its quiddity, comes from the burning of the agave heart."
— Ray Harvey, The Coloradoan, 19 May 2016

"An apparently intractable fact of life is that our thoughts are inaccessible to one another. Our skulls are like space helmets; we are trapped in our heads, unable to convey the quiddity of our sensations."
— Jason Pontin, Wired, 16 Apr. 2018

Did You Know?
When it comes to synonyms of quiddity, the Q's have it. Consider quintessence, a synonym of the "essence of a thing" sense of quiddity (this oldest sense of quiddity dates from the 14th century). Quibble is a synonym of the "trifling point" sense; that meaning of quiddity arose from the subtler points of 16th-century academic arguments.
And quirk, like quiddity, can refer to a person's eccentricities. Of course, quiddity also derives from a "Q" word, the Latin pronoun quis, which is one of two Latin words for "who" (the other is qui).
Quid, the neuter form of quis, gave rise to the Medieval Latin quidditas, which means "essence," a term that was essential to the development of the English quiddity.