<P> Attempts at explaining the origin of the phrase go back to the mid-19th century . One explanation favoured in a letter to the editors of Notes and Queries dated 1851, as well as by the Oxford English Dictionary upon their revision of the relevant entry in 2007, is literal interpretation of the saying, concerning the distinction of the lowercase letters p and q in the context of the school - room or the printing - office . </P> <P> According to Michael Quinion, "(i) nvestigations by the Oxford English Dictionary in 2007 when revising the entry turned up early examples of the use of Ps and Qs to mean learning the alphabet . The first is in a poem by Charles Churchill, published in 1763: "On all occasions next the chair / He stands for service of the Mayor, / And to instruct him how to use / His A's and B's, and P's and Q's ." The conclusion must be that this is the true origin ." </P> <P> When pupils were taught to write lowercase alphabet, the positioning of the vertical line before or after the circle represented different letters: d & b, p & q . Pupils had to also mind the placement of the letters when writing the alphabet eg . p comes before q . As noted by W.D. Henkle in Educational Notes and Queries in 1876, in this case the proper spelling of the phrase should be "note your p's and q's", because the distinction of majuscule P and Q does not pose a problem . </P> <P> Nevertheless, a number of alternative explanations have been considered as more or less plausible . Another explanation suggests that "Ps and Qs" is short for "pleases" and "thank - yous", the latter of which contains a sound similar to the pronunciation of the name of the letter "Q". Another proposed origin is from the English pubs and taverns of the 17th century . Bartenders would keep a watch on the alcohol consumption of the patrons; keeping an eye on the pints and quarts that were consumed . As a reminder to the patrons, the bartender would recommend they "mind their Ps and Qs". This may also have been a reminder to bartenders not to confuse the two units, written as "p" and "q" on the tally slate . </P>

Where did the phrase p's and q's come from