What’s the origin of the expression “mind your P’s and Q’s”?

Cecil replies:

As usual, we’ve got theories by the yard, facts by the angstrom. The more fanciful explanations for “mind your p’s and q’s” include:

It originated in British pubs as an abbreviation for “mind your pints and quarts.” Supposedly this warned the barkeep to serve full measure, mark the customer’s tab accurately, etc. It meant “mind your pea (jacket) and queue.” Queues (pigtails) were often powdered, and wifeypoo was telling hubby to keep the cruddy kid stuff off his collar. An even dumber variation of this involves “pieds,” French for “feet,” and says minding your p’s and q’s means combing your hair and polishing your shoes, or something like that.

P and q stands for “prime quality.” According to the Oxford English Dictionary, to be P and Q was a regional expression meaning top quality. It first shows up in a bit of doggerel from 1612: “Bring in a quart of Maligo, right true: And looke, you Rogue, that it be Pee and Kew.”

The simplest explanation is that the expression refers to the difficulty kids have distinguishing lower-case p and q, mirror images of each other. Mind your you-know-whats was thus a teacher’s admonition to students. Plausible? Yes. Sexy? No. Such is the fate of a slave to facts.

“On the qt,” meaning on the sly, secret, is easier. Most likely it’s an abbreviation of “quiet.”

Letters, we get letters

Dear Cecil:

When I took typography at the University of Iowa, I was told the expression “mind your P’s and Q’s” originated with printers who set headlines using movable type. If you’ve ever seen old type, you know the letters are mirror images of the regular alphabet. Lower-case P’s look like Q’s and vice versa. “Mind your P’s and Q’s” was a reminder not to mix up the letters when putting them back in the rack after use.

Printing also gave us another expression. Individual letters were called “sorts,” and if you used up all you had of a given letter, you’d be upset, naturally, because you were “out of sorts.”

— Marion E., Chicago

I was with you until that last turn, Marion. “Out of sorts”? Get serious.

Out of sorts over “out of sorts”

Dear Cecil:

I enjoy your column, but you made a mistake in suggesting that Marion E.’s explanation of the origin of “out of sorts” was wacko. Among my proudest possessions is a 1937 Webster’s Universal Unabridged Dictionary. Under “sort,” noun, first entry, definition number 6 reads: “In printing, a type or character, commonly one belonging to a font, … generally in the plural and in phrases; as, out of sorts, hard on sorts, etc.” I have been told by those “in the know” that the colloquial usage derived from the annoyance that one felt when typesetting came to a halt because the typesetter was “out of sorts.” Do I get an A?

— Jay H., Stoughton, Wisconsin

Yeah, for “amateur.” You’ve fallen prey to the common fallacy post hoc ergo propter hoc, the assumption that because two things follow in sequence the first necessarily caused the second. It’s true dictionaries juxtapose the two definitions of “out of sorts,” but they don’t say one inspired the other and indeed they would be foolish to do so.

If we turn to the Oxford English Dictionary, really the only thing for this kind of work, we find that the first known reference to “sort” in the sense of a character in a type font occurs in 1668. The first known use of the expression “out of sorts,” irritable, occurs in 1621. Other 17th-century quotes indicate you could use “out of sorts” to mean you were literally out of stock, caught short, broke. It seems reasonable that this general use of “out of sorts” was the origin of the modern expression, not printing in particular.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.