I hear people say " watch your P's & Q's", what does P's & Q's mean/stand for?

Question

I understand to "watch your P&Q's" means to be on your best behavior. Does the leters P and Q stand for something?

Answer 1

There is no definitive answer. The two leading answers are:

Pints and Quarts. From the time when waitresses had to pay for spilt beer - "mind them" means take care of them. It also told waitresses to keep track of how much money people were spending.

Another answer comes from the old days of printing; typesetting was done by actually choosing each letter and putting it in the type frame to be inked and then printed. Because the letters "p" and "q" look the same -- reversed -- there was often a mixup. Remember, that the letters appear backwards to the typesetter, so that they will show up in their usual fashion when they are pressed to paper. [The problem with this explanation, however, is that there is no similar expression for "b" and "d" -- two other letters that are reversed.

Answer 2

In the days when newspapers were set in lead type, the letters were kept in two boxes above the typesetting machine - the upper box contained capital letters, the lower box contained small letters (which is where we get the terms upper and lower case, just in case you're interested).

Apprentice printers were always told not to mix up p and q, since the two compartments were side by side, and it was easy to mistake a p for a q.
Hence, "Mind your Ps and Qs."

Isn't history fun?

Answer 3

One explanation is that it comes from the early days of printing, when movable type was positioned for printing. This process was done in reverse, so that the printed page was not-in-reverse. The lowercase letters p and q were
hard to distinguish, since in most designs they were mirror images of each other. "Mind your P's and Q's!" became a warning for the young children working in these print shops.

Answer 4

I think it is refering to the similarities between lower case 'p' and 'q'...they were easily reversed. Of course, if this analogy is true, it could have just as easily been 'Watch your b's and d's'......

Answer 5

They don't really stand for anything. It just means watch what you say.