On the QT

This means to keep something secret, but no one really knows why.

“QT” is considered an abbreviation of “quiet.” …but why? There aren’t a lot of answers.

Moreover, its punctuation and capitalized a variety of ways:

on the QT
on the qt
on the Q.T.
on the q.t.

The last two are particularly baffling, because it implies there are words for the “Q” and the “T,” which is just wrong.

From McGraw-Hill:

in secret; secretly. (From QuieT.)

Again, why? Since when do we abbreviate words using their first and last letters?

From Farlex:

q.t. is a humorous abbreviation of quiet

…again, why?

Why I Looked It Up

I was watching an episode of Friends where Ross was planning something in secret for Monica and Chandler’s wedding (he was going to play the bagpipes). They asked him what the secret was, and he said:

Nope, I’m keeping this on the QT.

Also, I remember Danny Devito’s character from L.A. Confidential who published a gossip magazine called Hush Hush. He used the phrase several times. For example:

Off the record, on the QT, and very hush-hush.