Dear tsuwm: can you tell us which one of these opinions is correct?
"One word that is said to have arisen from travelling by sea is `posh'. I read in a book, on British rule in India, that it is an abbreviation for `portside outward starboard homeword' to signify the best rooms in the ship to avoid the heat while travelling from Europe to Asia and back. However, the M-W Online Dictionary says that the etymology is unknown, and the word appeared in 1918."




This is from Mike & Melanie, at the Burnside site:
"Believe it or not, we have been waiting years for someone to ask this question as pal is one of the very few English words which derives from Romany (posh is another)."