<P> Mind your Ps and Qs is an English language expression meaning "mind your manners", "mind your language", "be on your best behaviour" or similar . </P> <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>

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