Posted by James Briggs on May 28, 2000
In Reply to: P's & Q's posted by Nolan on May 28, 2000
: Hi A!
: Can't find what it means anywhere and now it's got me currious...
: Any help appreciated.
: And yes I'm not native English speaking.
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.