@joyR
POSH has long been accepted as "Port Out, Starboard Home," and has been widely used so it's existence is indisputable.
From the same dictionary.com link I posted above.
According to folk etymology, posh is an acronym for Port Out, Starboard Home. This myth from the 1930s says that rich people booking steamer trips staying in the nicer, round-trip cabins would have P.O.S.H. stamped on their tickets. After decades of searching, there's never been any evidence such a practice ever existed.
And from Mirriam Webster:
https://www.merriam-webster.com/words-at-play/posh-history-and-meaning
I was looking up the etymology of 'posh', and you say its origin is unknown, but you're wrong. Everybody knows 'posh' stands for "port out, starboard home."
Supposedly, 'posh' stands for "port out, starboard home." There's only one problemβwe have no evidence to back that story up.
For those who don't know the story, here it is: on ocean voyages between Britain and India, the most desirable cabinsβthe ones that didn't get the afternoon heatβwere on the port side out and on the starboard side home. These luxury tickets were supposedly stamped with the letters POSH: posh.
This is a great story. It's tidy, it's historical, and it conjures up pictures of women in bustles and skirts swooning onboard ships. And it's an acronym! Who doesn't love an acronym! Great story! But that's all it appears to be.
It's not that we don't like this etymologyβit's that we have no evidence for it. We have seen no tickets stamped with POSH; we've found no magazine articles talking about this fashionable mode of travel. Here's what we have found: posh entered the English language early in the 1900s, in a wholly un-nautical context, to mean "smart" and "stylish." Try though we might, we can't find any definitive information on its origins.
But if you find an old transoceanic ticket in your attic that's stamped "POSH," let us know.
The existence of the POSH acronym is very disputable.