What does ps stand for and why do people say pss and psss at the end of their letters?

ps == PostScript. It's latin. "post" means "after" and "script" means "writing". If you write something after the postscript, then that is a post-postscript, or pps, and something after THAT is ppps. I don't know why people write "pss" and "psss". Perhaps they are confused, or perhaps you read it incorrectly.

And if you see NB, that stands for "nota bene", or "note this well".

its stands for post script. technically they should write pps and ppps for additional items!

Actually, the Latin is "Post Scriptum".

Never heard of PSS or PSSS. If you didn't mean PPS and PPPS, then maybe what they meant to say was "pssst" - as in "listen carefully -- I'm about to tell you a juicy secret."

It is post script, and people should not write pss or psss etc.

It should be:

Ps. for post script.
Pps. for post-post script.
Ppps. for post-post-post script!

But really people shouldn't go so far to have that many post-scripts. You leave post-scripts after you have finished your answers.


ps.
I should have mentioned that Script is short for Manuscript. Its supposed to be used for documents written by hand.

pps.
I am bored!

To add to other answers. Post scripts were often added to documents after the document was "finished". For example, let us assume that you were writing a letter and you finished and signed the end of the letter. However, you then remember something else that you want to include. You would then add that additional information as a post script after your signature rather than making the letter look messy by scratching out the signature and/or copying the original letter to a new sheet and then adding the additional material before signing the new letter.

However, in our era computer aided word processors, we can now compose documents without having to put them on paper from the beginning. So, when we think of something that we want to add to the document, we can do so without having to use a post script. We can just move the appropriate text and insert the new information. Because of this post scripts are falling out of use.

Just to add some more Post Script info!

PSS is also valid and means "post sub-script".

x

Actually, the "script" means "written," not necessarily hand-written.

Yeah, post-script is what it stand for, as others have mentioned. People say psss at the end because they want to attract your attention in a cheesy TV show kind of way.

I think after people read the correct answer they should no longer post and bore everyone.

Just a thought.

Poo stain

It Means Peeing Simultaneously.