What Is Origin Of....

[zylaphone]

"Mind your p's and q's come from?

[Jackdaw33]

It is said to come from the custom of innkeepers chalking up drinks so the customer could pay at the end. P stood for pint and Q for quart (two pints). If the innkeeper mixed them up he would be out of pocket. Also, P and Q in lower case are almost mirror images so it would be easy to make a mistake.

[Jackdaw33]

Another theory is that P stands for Please and Q for Thank you.

[Fitzer]

I believe it came from the print trade where when setting up the type for the press you had to be careful to get the correct one, as in lower case and back to front (as they are in print type) they would be easy to confuse.

[Jackdaw33]

Yet another theory from Fitzer. The truth is, no-one really knows.

[Canary42]

Several versions here

http://blog.oxforddictionaries.com/2012/01/origin-to-mind-your-ps-and-qs/

[dannyk13]

According to Brewer's fitzer is correct.It was a warning to printer's apprentices.

[Peter Pedant]

fitzer or else sorting out the type in order to reset it for another

the pile of unsorted print was called a printers pie
and the young kid who sorted them back into their boxes was a printers devil

the publican
well of course if he chalked up pints as quarts then he would be IN pocket and the customers would have to mind their ps and qs .....

[Peter Pedant]

// It was a warning to printer's apprentices.//

printers' devils ....

[Jackdaw33]

My mother often used this phrase when going visiting. It was a reminder not to forget to say Please or Thank you. Obviously a derivative.

[Gromit]

I learned to set printers type, and we were told that mistaking pq was an easy error, that we should be careful not to make.

[zylaphone]

Jackdaw, it was thinking. Thank you all so much.