Definition 1 of 1
There are many theories about the origin of the word posh. One theory is that posh is in fact an acronym, standing for Port out, Starboard home. It refers to the fact that on sea voyages between Britain and India, the most comfortable (in terms of being cooler) and therefore most expensive cabins on ship would be on the port side going out, and the starboard side coming back. It was further suggested that the Peninsular & Oriental Steam Navigation Company issued tickets for the more expensive cabins on this route with the letters P.O.S.H., and that this is where the origin lies.
Added 2012-07-22 by Dishoom Dishoom