September 11 attacks, September eleven attacks, September eleventh, Nine-eleven? None of the above?

What's recommended for formal writing?

4 Answers 4


I think your question uses the most readily understood and formal way of referring to the events of that day: September 11 Attacks. Indeed, that's the name of the Wikipedia page.

9/11 (nine-eleven) is the informal "shorthand" that usually comes from people wanting to either exploit the event to push an agenda or bring out a more emotional response. Personally, I'd avoid using it in formal writing.


If you are writing for posterity (as opposed to writing for a periodical or something of similar, limited currency) I would introduce the event as "the attacks of September 11, 2001". We are nearly a decade out now, and people have a horrible habit of memorializing one such event with another, similar one. That leaves aside consideration of mere coincidence -- Ireland now has two Bloody Sundays, so when discussing the particulars of one or the other, you need to distinguish which one you are talking about. (Both carry the same emotional resonance if they're just mentioned in passing.)


Also please take in account that "9/11" can be misleading to most of the world. There are already a lot of people, who think that the attacks have occurred on 9th of November.

The issue is, that USA is almost the only country in the world, which uses MM/DD/YYYY date format.

See: http://en.wikipedia.org/wiki/Date_format_by_country

  • 1
    The many countries who use YYYY/MM/DD would not confuse 9/11, but your point still stands.
    – Kosmonaut
    Feb 24, 2011 at 14:56
  • Well, maybe more than the date format is more about the way you're talking about dates. Eg. would you rather say "11 September" vs "September 11"? AFAIK, the first form is used in British English, also more natural for non-English speakers in Europe.
    – vartec
    Feb 24, 2011 at 15:30
  • @Kosmonaut: That depends on whether the countries that use YMD (China, Korea, Japan etc.) use MM/DD or not when the year isn't present. :-) This cannot exactly be inferred from their format for the full date. For instance, in India which uses DMY, when talking of just the month and date, DD/MM is universal (like the "26/11" terrorist attacks in Mumbai), but when spelling out the month in words, both "26 November" and "November 26" (and "26th November" and "November 26th", in speech) are common. Each country has its own mess; always best not to assume anything! Feb 26, 2011 at 7:46

If you want to avoid a mere reference to the date, you could say "WTC Attacks" or "Twin-Tower Attacks", though this only includes the two most prominent attacks—not the other air planes, which crashed elsewhere and killed fewer people. Note that there should be a hyphen in "September-11 Attacks" and "September-Eleven Attacks".

  • 2
    Why should there be a hyphen? I don't recall ever seeing it written in print with a hyphen…
    – ghoppe
    Feb 24, 2011 at 15:52
  • @Ghoppe: Well, I suppose opinions may differ. But it is after all a compound adjective ("which attacks?" — "the September-11 ones"), and it is most convenient to use hyphens universally with compound adjectives. Hypothetically, a hyphen is needed because the second part of the c.a. could wrongly be taken to modify the head noun first: "which attacks?" — "the 11 attacks" — "huh, which 11 attacks?" — "the September ones". This is of course not very realistic; but I feel that consistency is more helpful in the case of this rule than occasional exceptions based on practicality. Feb 24, 2011 at 16:02
  • 3
    I see, so you're using should in the sense of there aught to be rather than pointing out that it's usually written that way. ;-) Personally, I think you're being too prescriptive. A hyphen isn't needed in compound adjectives if there is no ambiguity. (e.g. Saturday morning cartoons.) -- Even more so with dates. No one writes July-fourth celebrations.
    – ghoppe
    Feb 24, 2011 at 16:22

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