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I learned that in modern Greek tau is called taf. So I guess the letters here are pronounced in ancient Greek? — Preceding unsigned comment added by (talkcontribs) 15:16, 10 March 2004 (UTC)

It is written ταυ, which is pronounced roughly "taf", because υ takes on a sound varying between "f" and "v" when it follows an α or ε. --Delirium 03:39, Mar 4, 2005 (UTC)

Usage in engineering[edit]

Can anybody tell the significance of tau usage in engineering industry at present? — Preceding unsigned comment added by (talkcontribs) 03:54, 1 April 2007 (UTC)

Tau is used for shear forces in both solid mechanics and fluid mechanics. See Navier-Stokes Equation (see Cauchy stress tensor) and Shear stress Rememberlands (talk) 06:05, 17 January 2013 (UTC)

Not a Chinese family name[edit]

Tau isn't used as a Chinese family name. A similar-looking character is used but it's not tau. The hook at the bottom is on the left in this Chinese character. —Preceding unsigned comment added by (talk) 03:03, 3 September 2009 (UTC)


  • Creating section "Miscellaneous" at the bottom of the article
  • Moving the off-beat "essay" to "Miscellaneous". The letter sigma argues that tau shouldn't be included in the alphabet, on the basis that tau's shape resembles the scaffolds used for crucification? That has "wtf" written all over it.
  • Introducing section "Scientific uses" as the first one--this is the most important thing to readers
  • Introducing section "Other uses"
  • Bayer stellar designations use pertains to astronomy--moving to "Scientific uses"
  • "General Tau Theory" use looks strange. The page on the topic has the insufficient context template and features lots of gibberish. I can't distinguish if this is science or pseudoscience. Moving to "Other uses".

-- 09:36, 30 April 2007 (UTC)

Edit request from Startupgrrl, 21 October 2010[edit]

{{edit semi-protected}} Should "The circle constant of one turn, the ratio of a circle circumference to its radius, 6.283...,[1] equal to 2π" be listed as the VERY FIRST scientific use?

No one but the guy in [1] uses tau like that. In fact, the published mathematician he cites for justification suggests an entirely different symbol (pi with a third leg).

How about knocking it down a few pegs (or removing it entirely)?

Startupgrrl (talk) 07:39, 21 October 2010 (UTC)

Done Thanks, Stickee (talk) 08:33, 21 October 2010 (UTC)
Please see my argument below. I'm not that guy btw, but the topic of 2pi being the "more natural" constant than pi is widely known (and really not as absurd as it sounds). IMO it's a beautiful example of how humanity can collectively get things wrong and be stuck there. Either way, it's notable, obviously not standard or common usage, but it should get a mention as "has been suggested as ..." or something like that. I'd have added it by now (at the bottom of the list, obviously), if it weren't for this stupid semi-protected status. Frankly it surprises me I can't find anything on the subject of 2pi anywhere on Wikipedia. — Preceding unsigned comment added by (talkcontribs) 11:32, 18 February 2011 (UTC)

6.28[edit] Should the use of τ as 2π be mentioned? (talk) 15:27, 19 November 2010 (UTC)

No. Wikipedia is not a place for activism. Until the use of τ as 2π becomes a common, standard usage rather than just a small number of activists trying to create a new convention, then adding it here is basically original research. Benwing (talk) 04:16, 20 November 2010 (UTC)
Yes. It's nothing to do with "activism". I came to look for "tau as 2pi" here. So what if it's not common, standard usage?? I agree that it's not actually used in scientific literature, but (for now) only in the context of "pi should have been 2pi and all our formulas would be shorter and clearer". However, the idea that pi would have been better defined as 2pi is widely known and notable among everybody I know that has a professional/scientific interest in Mathematics whether they agree with it or not, they are familiar with the idea. Therefore it makes sense to at least "Tau has been suggested as a symbol to represent the constant 2pi or 6.28... [1][2]". I agree that it shouldn't be made to look like it's actually common or standard usage, but it should at least be mentioned somewhere. I'm frankly surprised that I can't find anything on the topic on Wikipedia, regardless of whether in connection with tau or just in general. — Preceding unsigned comment added by (talkcontribs) 11:19, 18 February 2011 (UTC)

Edit request from, 8 March 2011[edit]

{{edit semi-protected}} Tau is also being used as the ratio of a circles circumference to its radius, e.g. 2pi


and (talk) 17:07, 8 March 2011 (UTC)

X mark.svg Not done Neither of the sources you provided are reliable sources. The former is a personal site, not endorsed by the educational institution, and the latter is ... well... not reliable. Please find a source that demonstrates this use in a reliable reference. Thanks, Shirik (Questions or Comments?) 06:48, 14 March 2011 (UTC)

A math publication is a reliable source(the personal page is mentioning the article). But we're talking about mentioning the proposal, which has a encyclopaedic value in itself, not stating that it has any general usage. —Preceding unsigned comment added by (talk) 17:51, 14 March 2011 (UTC)

Tau day[edit]

no mention of the movement to teach tau instead of 2pi? it's certainly notable —Preceding unsigned comment added by (talk) 15:15, 14 March 2011 (UTC)

I've added it as a "popular-culture notation" in this edit, since that's its only source of notability. It is referenced here and there in the press, as you demonstrate, so readers coming to this page would benefit from a link to the article. That said, the notation has no usage in the scientific literature, and we should be careful not to imply that it does. Melchoir (talk) 17:09, 14 March 2011 (UTC)
This is not notable what-so-ever. It should be removed. Quandle (talk) 19:10, 14 March 2011 (UTC)

Edit request from WeizenUte, 14 March 2011[edit]

{{edit semi-protected}} The article has an incorrect citation. The citation for [2] indicates that Bob Palais suggested that tau represent 2pi is incorrect. Palais' article is found at his website here, and nowhere in the article is mention of tau. However, on Palais' website,, he mentions that he has be contacted by individuals wanting tau to represent 2pi. This may be nitpicking a source, but it is in fact Michael Hartl who is working to make tau to represent 2pi. His "manifesto" is given at, Please correct the changes to accurately reflect the sources content. Professor Palais' article discusses the illogical nature of pi, with no discussion of tau, whereas Hartl's article seeks to give 2pi a specific name tau.

WeizenUte (talk) 20:26, 14 March 2011 (UTC)

Not done: {{edit semi-protected}} is not required for edits to semi-protected, unprotected pages, or pending changes protected pages. GFOLEY FOUR— 02:05, 15 March 2011 (UTC)

tau as 2pi[edit]

While I agree that the usage of tau as 2pi is not common, it deserves a mention. As someone who works with fourier transforms, hbar, and so on quite often, I've thought the same thing many times. I think it's cute, and a breath of fresh air, to see a reasonable proposal for a 2pi symbol. Not including any mention of this phenomenon is ridiculous. At LEAST there needs to be a reference to this as popular culture: TAU DAY. -- (talk) 06:22, 6 April 2011 (UTC)

The only reason people include this is because they want it to become popular. That's backwards to how wikipedia should work. I suggest removing it. --Quandle (talk) 11:31, 6 April 2011 (UTC)
When lots of people are asking for the inclusion of a subject, that's also often a sign that it IS popular. I agree that the subject may not be noteworthy at present other than pop-culture permeation, but at what threshold does something become worthy of mention? Tau Day has been featured on Fox News, CNN, Slashdot, and, to name a few popular sources. To not mention it here at all seems rather odd. --TricksterWolf (talk) 22:24, 28 June 2011 (UTC)

I read about Tau as 2pi for the first time today in a BBC article, which was the first time I thought about the concept that 2pi actually seems like it should have its own notation. Not including this concept on the page leaves the page with less information than is available about Tau. If Tau is not picked up as a standard then the information can be limited later, but right now there is a debate about whether to use Tau in such a way, the page should reflect that at this time. -- (talk) 04:24, 29 June 2011 (UTC)

Apparently you didn't read the page in full. See the last entry under "Scientific uses". --Cybercobra (talk) 08:08, 29 June 2011 (UTC)

The explanation of the application of pi in various equations that require it to be multiplied by 2 is not so apparent, which is the information that would give context to the proposal for the adoption of tau as the standard. Some might see this elaboration to be lobbying, though not having this information might be seen as the same. (talk) 06:53, 30 June 2011 (UTC)

6.28 is constant for circumference of mobius strip[edit]

6.28 is the constant used to find the circumference of a mobius strip. This should be mentioned on Wikipedia. — Preceding unsigned comment added by RobotHeroLove (talkcontribs) 03:56, 16 April 2011 (UTC)

Source? --Cybercobra (talk) 07:25, 16 April 2011 (UTC)
Right now it is Original Research, but if you look through old math books, I'm sure you'll find something about it. — Preceding unsigned comment added by RobotHeroLove (talkcontribs) 19:11, 16 April 2011 (UTC)
This sounds like merely one application of the τ = 2π definition, which we already mention. --Cybercobra (talk) 20:39, 16 April 2011 (UTC)

tau = 2pi[edit]

Wikipedia is not the place for activism. I have removed this again because it's not notable. That a few people write tau to mean 2pi is not knowledge relevant to anyones mathematical development. Please try to justify why this usage should be included before reverting. Quandle (talk) 15:32, 1 July 2011 (UTC)

I agree that we shouldn't overemphasise or misrepresent anything. However, you seem to be saying that something being activism inherently makes it not notable; but in reality it's more accurate that the converse is true. The Wikipedia is supposed to document knowledge about the real world, and if activism is appearing and being discussed in major news sources then that activism is ipso facto notable, the BBC and CNN are conferring notability on it. -Rememberway (talk) 16:11, 1 July 2011 (UTC)
Otherwise taking your argument literally to its logical conclusion, other articles like enviromentalism, we would have to delete that, along with very many other pages. -Rememberway (talk) 16:11, 1 July 2011 (UTC)
Sorry if I was unclear, I meant this: tau=2pi is not notable. Adding it to Wikipedia counts as activism. The reason people are so persistent in having it on Wikipedia is because they feel it lends legitimacy to their movement. This is the opposite of what should be happening. Quandle (talk) 21:34, 1 July 2011 (UTC)
Please try to come to a conclusion here instead of trying to cause an edit war Quandle (talk) 21:33, 1 July 2011 (UTC)
So far as I know the guy that coined 'tau' has not asked for it to be on the Wikipedia, nor have the people that reverted you expressed a view that it being here 'lends legitimacy'. What makes you think that that's why people are adding it to the Wikipedia, rather than to simply document a viewpoint that has been made notable by its publication by the various major news services that have covered it?
It seems to me that that you are editing based on a bad faith assumption unless you have any actual evidence to that effect. -Rememberway (talk) 21:49, 1 July 2011 (UTC)
The real problem with activism is when people put stuff in the Wikipedia prior to getting publicity first.
But that's not what's happened here. Putting things that have had publicity in the Wikipedia isn't bad or wrong it's totally normal; nor is it wrong to add things that have artificially publicised, most things that have been added in the Wikipedia have been knowingly publicised, books, films TV programs, and yes, even activism of various forms. -Rememberway (talk) 21:55, 1 July 2011 (UTC)
I just checked your userpage looks like you have a vested interest, no wonder you kept reverting without discussion and claimed there was a consensus when there were exactly two opposing views. I'd like to come to an actual agreement about this so I hope you will break my expectation (which is that you'll likely just continue to ignore me and automatically revert my edit). Quandle (talk) 02:25, 2 July 2011 (UTC)
Let's examine your position again. Am I to understand that you are claiming that the Wikipedia should have nothing whatsoever about a subject that has been written about in multiple reliable sources, has been in the news and when googled has tens of thousands of hits; that when tau day occurred alone, caused this page to get 20 thousand hits. Am I to understand or even believe that you think that it's right and proper to completely censor every trace of tau from the Wikipedia, simply because somebody, somewhere thinks that tau is a good idea, and hence in your eyes this constitutes 'activism' and hence in your eyes is inherently disreputable? -Rememberway (talk) 03:15, 2 July 2011 (UTC)
With all due respect, I don't think you understand what the Wikipedia is, or what it is for. It's not here to 'right wrongs' to protect Pi, or promote Tau. It's here to supply notable information; and like it or not, this information has been judged by CNN, BBC, Fox News, New Scientist, The Daily Telegraph etc. etc. as being notable, and hence our users will be searching the Wikipedia for it, and therefore we should supply it. Any other position is incompatible with the Wikipedia policies. We do not censor things we don't like. That is ALL. -Rememberway (talk) 03:15, 2 July 2011 (UTC)
I think you are intentionally "misunderstanding" what I was trying to say, but anyway let me restart it simply: This tau = 2pi nonsense is just an opinion piece that someone wrote and a few people (clearly yourself included) adopted. These people want tau to become standard (taught in schools etc.) therefore they are interested in promoting Tau. One way I think they (you) are doing this is by plastering it all over wikipedia. I consider that activism.
I agree that wikipedia is not supposed to promote Tau, that is the reason I removed it. It has been added yet again without any more discussion so it really feels like none of you tauists are interested in discussion. Quandle (talk) 14:19, 2 July 2011 (UTC)
I'm just a visitor and I came here to use this article in some of my documents which references tau as 2pi because that is my preference. I'm only here on this discussion page to offer my tally mark for tau being cultural significant -- I don't care anything about it's promotion I just wanted there to be supporting reference. After briefly reading this page you appear to be the one who is bringing the least amount of items to the table for discussion. You've only been arguing from ignorance providing no evidence and repeating tau is only an item of promotion when it's not being promoted, it's only being mentioned. I'm not an expert on the rules of wikipedia but I'm pretty sure all there needs to be in order to justify the mention is a reputable source for citation which there is. I don't mean this as an ad hominem because I don't know how else to phrase this but you appear as though you would be, if not already, the first one around here to violate wp:npov by using this article to promote their own point of view whether that be by adding or subtracting. (talk) 13:19, 4 July 2011 (UTC)
I agree that using tau for 2π is not a common usage. I guess I don't see why it is so obscure that we can't even mention it, given the large number of sources covering it. Sure, the working mathematician is unlikely to encounter tau used this way, or even \pi\!\;\!\!\!\pi, but working mathematicians are not the only ones who read wikipedia. Kingdon (talk) 14:38, 3 July 2011 (UTC)

I read about the use of Tau to represent 2pi at BBC, and came to this page to learn more about how it would be applied in various equations. There is hardly any information on this page at all, and now I see that there are people who specifically think that including such information is a matter of activism. How about trying to present as much sourced information as possible? This is not a matter of someone pushing tau, and so others have to push back. If there is a drive to create a standard out of tau that has garnered international press, what is the motive to keep the relevant information off the page? (talk) 02:10, 4 July 2011 (UTC)

It's the wrong page. That use of tau was noted on this page, but the details should be in a real article, such as Pi. — Arthur Rubin (talk) 06:37, 4 July 2011 (UTC)

Why not both? I wanted to find out about the usage of tau as 2pi so I came to this page, which I imagine quite a lot of people do. (talk) 06:48, 4 July 2011 (UTC)

The alleged use of τ as 2π is a minor use of τ, and probably not primary, even as a mathematical constant. Perhaps we should work in a link to Pi#Criticism somewhere in that line, but I can't find a good place. — Arthur Rubin (talk) 09:19, 4 July 2011 (UTC)

I object to the non-notability of tau as 2pi. These are my example sources: Fox News CBS News BBC News MSNBC The Tau Manifesto

And many more (Google News): [1]

Four secondary sources: all are from major news networks, all are independent of the subject, online, in English, with the main topic being Tau day or the Tau movement. One is the main primary source, specifically on the proposed tau=2pi definition. Mention in the BBC, CBS, and Fox News is, in my opinion, "significant coverage" from secondary "reliable sources," "independent of the subject." This warrants at least a passing reference. Visitors (including myself) will be and have been looking for this definition of tau. Inclusion of a reference to tau as 2pi does not constitute an endorsement of the idea nor does it necessarily convey that tau is commonly used as such in math and science. If that is a concern for you, then the reference may be worded to avoid such confusion. For example: "Tau is also a proposed circle constant equal to 2pi.[2] In the current scientific and mathematical literature, tau nearly always refers to other meanings of tau. For more information, see Criticism of Pi."

SebastianJB (talk) 21:15, 4 July 2011 (UTC)

Edit request from Matteach, 15 September 2011[edit]

{{edit semi-protected}} This is not an edit, but an addition. You may add that Simcha Jacobovici touches upon this topic in his Naked Archaeology show entitled "Bethsaida". In this episode an ancient first century CE cross symbol was found at Bethsaida, one of the earliest Christian sites.

Matteach (talk) 15:39, 15 September 2011 (UTC)

All requests to edit semi-protected articles must be accompanied by reliable sources - please give a specific link to some reputable publication of the claim, and re-request. Thanks,  Chzz  ►  01:05, 17 September 2011 (UTC)

X mark.svg Not done

Mathematics, nested radicals[edit]

I find this perhaps just a little odd. I don't know who created this site but apparently they believe that tau is used for the nested radical constant. I'm not sure if this is actually a common notation, but if it is, then it should be included, that is, that:
\tau = \sqrt{1+ \sqrt{2+ \sqrt{3+ \sqrt{4+ \sqrt{5+ \dots }}}}}
just trying to be halpful! (talk) —Preceding undated comment added 05:00, 19 October 2011 (UTC).

Warhammer race[edit]

Am I the only one who knows that there's an entire race named the "Tau" in the Warhammer 40,000 universe? Couldn't that be noted in the trivia or something? — Preceding unsigned comment added by Pepertje (talkcontribs) 01:03, 29 February 2012 (UTC)

An extraordinary claim requires extraordinary proof.[edit]

"Tau was derived from the Phoenician letter taw"

Any scientific proof to back up this extraordinary claim?

Encyclopedic content... not.

(TheSkepticScholar (talk) 22:45, 4 July 2013 (UTC))

It's history, not science. There's more detail, with references, at Greek alphabet#Origins, which article is linked in the first sentence.--JohnBlackburnewordsdeeds 23:23, 4 July 2013 (UTC)