Posted by ESC on April 28, 2002
In Reply to: Re:mind your p's and q's posted by ingrid on April 28, 2002
: I heard it stould for mind your punctuation and quotes
That's a new one. From the archives:
There have been several theories posted on Phrase Finder about "minding your P's and Q's." To mind your Ps and Qs is to be careful; cautious. The Ps here are said to be pints and the Qs to be quarts. The publican "chalks up" or "puts on the slate" the drinks supplied to customers; they must be aware of how much they have drunk or their bills will be unexpectedly large.
An alternative view is that P derives from the French pied=foot and the Q comes from queue=tail(of a wig) and that the whole saying is based on 18th century court etiquette.
Advice to a child learning its letters to be careful not to mix up the handwritten lower-case letters p and q. Similar advice to a printer's apprentice, for whom the backward-facing metal type letters would be especially confusing.
An abbreviation of mind your please's and thank-you's.
Instructions from a French dancing master to be sure to perform the dance figures pieds and queues accurately.
An admonishment to seamen not to soil their navy pea-jackets with their tarred queues, that is, their pigtails.
There was once an expression P and Q, often written pee and kew, which was a seventeenth-century colloquial expression for "prime quality". This later became a dialect expression (the English Dialect Dictionary reports it in Victorian times from Shropshire and Herefordshire).
OED2 has a citation
from Rowlands' Knave of Harts of 1612:
"Bring in a quart of Maligo, right true: And looke, you Rogue, that it be Pee and Kew."
Nobody is really sure what either P or Q stood for. To say they're the initials of "Prime Quality" seems to be folk etymology, because surely that would make "PQ" rather than "P and Q".