Where does the word POSH come from?

Where does the word POSH come from?

Shopcurious.blogspot (2011)

Being an elegant and well dressed is what is called being a posh person. The origin of this word came from this old story, according to Kieran Mcgovern (2012) "The story goes that the more well-to-do passengers on ships travelling between England and India used to have POSH written against their bookings, standing for 'Port Out, Starboard Home' (indicating the more desirable cabins, on the shady side of the ship) ".

Bibliography:

Mcgovern K. (2012). Where does the word 'posh' come from?. Available at: http://www.englishlanguagefaqs.com/2012/04/where-does-word-posh-come-from.html (Accessed: 13/6/2013)

Shopcurious.blogspot (2011). Dressing down for toffs. Available at: http://shopcurious.blogspot.co.uk/2011/06/dressing-down-for-toffs.html (Accessed: 12/6/2013)