People use "N.B." at the end of a writing (say, a letter) to add a piece of information.

Equally, I find people using "P.S." in the end of a writing (usually, a letter) to add a piece of information.

Literally, "N.B." stands for "Nota Bene" and "P.S." for "Post Script". But, I find people using them interchangeably. Has the difference between them eroded over the time?

What is the correct scope of their usage?

  • 3
    "Nota bene" means "mark well" or something to that effect -- the equivalent of saying "Important!". "Post script" simply means something written after the the main letter was written -- an afterthought. The two are the antithesis of each other.
    – Hot Licks
    Dec 24, 2015 at 3:02
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    @HotLicks is right. I think the confusion arises from the fact that a final statement could either be an afterthought or the important message the writer wants the reader to take note of. Thus N.B and P.S. may appear in the same place despite their difference.
    – Chris H
    Dec 24, 2015 at 8:02
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    The N.B. need not be at the end. There could be multiple N.B.s throughout the document.
    – GEdgar
    Dec 24, 2015 at 15:56
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    @GEdgar is correct. But, usually (but not always) important things are written, as a reminder to the reader before leaving, at the end. This is perhaps where "Nota bene" and "Post Script" find them at the same place. Jul 7, 2016 at 3:32

3 Answers 3


Nota bene is usually used in letter or documents to attract the reader attention to an important aspect or fact, postsctiptum usually refers to an additional note to what has already been written.

Nota bene:

  • (imperative) Take special note; used to add an aside or warning to a text.

Usage notes:

  • As with the Latin phrases id est and exempli gratia, nota bene is now more commonly encountered in its abbreviated form n.b.
  • In Latin, notā is the singular present active imperative form of notō ‎(“I mark”, “I note”, “I observe”), whose plural equivalent is notāte; consequently,in English, when addressing an audience of more than one person, the plural form notate bene is occasionally used instead of the singular. This practice is not necessary in English;

  • nota bene is regarded as correct usage irrespective of number by all but the most pedantic language users. The abbreviation n.b. may stand for either.


  • Used to indicate a footnote at the end of a letter. Generally abbreviated PS or similar (ps, p.s., etc).

    • Addenda following an initial post script are often abbreviated PPS or similar (p.p.s, P.P.S, etc), indicating "post post scriptum".'


  • Is there "n.n.b."?
    – Pacerier
    Mar 28, 2017 at 23:54

"Nota bene" means "mark well" or something to that effect -- the equivalent of saying "Important!". "Post script" simply means something written after the the main letter was written -- an afterthought. The two are the antithesis of each other.

  • 1
    Do you have a source to support this?
    – JJJ
    Oct 1, 2018 at 11:26
  • @JJJ - Several dictionaries.
    – Hot Licks
    Oct 1, 2018 at 11:40

The practical answer is, almost no native English speakers use "N.B.". I don't recall ever hearing of this abbreviation before reading this post.

So I'm no help to you on "N.B.", but perhaps I can answer half your question.

"P.S." technically stands for "post script", as you say, meaning "after signature". Originally it referred to an additional comment that someone added to a letter after signing it, and which he therefore wrote below, i.e. after, his signature. In the days before word processing, when you wrote a letter directly on paper (barbaric idea, I know), if you completed a letter and signed it, and then something else occurred to you that you wanted to say, you wrote "P.S." below your signature and then added the additional thoughts. There was no way to add additional text above the signature and there was no easy way to cleanly erase a signature, so the only alternative would be to tear up the letter and start over.

The term has come to mean an afterthought or tangential comment. Today it's common to write "P.S." and such comments even if you haven't signed the letter. Like people will write emails, make their main point, and then write "P.S." and some tangential point. For example, "We have scheduled a meeting for Monday to discuss the Miller account. Please be prepared to present your findings on the cost benefit analysis. P.S. Don't forget we have a staff meeting next Thursday." The writer might set off the comment about the staff meeting like this with a "P.S." to indicate that it has nothing to do with the rest of the email. It is an unrelated comment.

Perhaps there is some particular profession or academic area where "N.B." is used commonly? I'm not familiar with it.

  • 6
    Jay, I'd have to disagree with your first paragraph; I use the term regularly, and at a very large computer company one of the support guys that I talk to regularly uses it frequently to draw attention to critical points. One of us is Australian educated, the other is an ex-Marine from the US of A, so demographically we don't fit a narrow niche. I've seen it in a lot of technical books over the years though I couldn't point you to a specific instance off the top of my head.
    – Alan K
    Dec 24, 2015 at 3:32
  • @AlanK Could be. I can only say that I do not recall ever seeing it used, and I think I'm pretty well educated and well read. Maybe I've seen it now and then and glossed over it. I work in the computer business too so if it was common in that industry but not elsewhere, I'd be among the first to know it. I'm not saying you're wrong, just that I can't corroborate your statement.
    – Jay
    Dec 24, 2015 at 3:36
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    I'm from a non-English speaking background, but in my studies of the English language, I have frequently come across N.B. In my experience N.B has always been used to emphasise a certain point relating to a topic already mentioned in the main letter. e.g "There's a meeting on Monday etc etc. N.B Everyone needs to bring their BA."
    – Thursagen
    Dec 24, 2015 at 4:10
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    @Jay great summary of P.S. and well-written. I have seen N.B. a reasonable amount, but not anywhere close to as frequently as P.S. It strikes me as somewhat more formal and/or academic, but that may be merely because of its less frequent use. In any event, if you can augment your answer with research on N.B., it would be an excellent candidate for an accepted answer and I'm sure that it would be upvoted. As Hot Licks correctly noted above, N.B. means "Please note! This is important! Pay Attention!"
    – Nonnal
    Dec 24, 2015 at 4:26
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    Just a quibble. Post script means "written after" in Latin. So a postscript is an addition written after the author originally concluded his message. Usually (and especially for a letter) this would be after the signature, but the words don't actually refer to a signature.
    – deadrat
    Dec 24, 2015 at 6:15

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