Short form that you might not know what its stand for

You must always write down 'P.S' below your letter or even in the post
at your blog right? Do you ever think of what is actually it stand for?

P.S is stands for postscript.
It means something added after a letter
or other written communication. like to add a detail.

What about R.S.V.P that always found in many invitation card?
It's actually comes from the French phrase,
répondez s'il vous plaît
which translates into English as "Please respond."

This means the host would like a response as to
whether you will be attending or not.
This is important when planning parties
to have seating and food for the correct number of people.

Next, you might be familiar with this short form of 'etc'
This one come from the word Latin, et cetera mean
'and other things' or 'and so forth'

The phrase et cetera is often used to delete the logical
continuation of some sort of series of descriptions.

For example, in the following expression...
We will need a lot of bread: wheat, granary, wholemeal, etc.

the "etc." stands for "and other types of bread".
It is an error to say or write "and etc."
in which the word "and" would be redundant.
This would translate as "and and the rest".

after etc we must put full stop too. not comma. ;)

Some more! em... what about 'e.g' and 'i.e' that
we always use for the short form of example?
I can't see the letter x in that short form o__O??

Those short forms also come from Latin word where
e.g : exempli gratia (for example)
i.e  : illud est (that is)

you know what. 'e.g' and 'i.e' are not the same! people
always misuse it include me. read for more detail [here]
hm... =__="

So, what is the other short forms that across your mind now?
Do you know what those stand for? :)