Talk:Decade

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Discussion

 * 109 years - aeon – 106 years - eon – 103 years - millennium – 102 years - century – 101 years - decade – 100 years - year
 * deka-annum/deca-annum/decka-annum (Da/da/daa/dka) - 10e1 years (annum)


 * annum (a) - kilo-annum (ka) - mega-annum (Ma) - giga-annum (Ga)

0 to 9 or 1 to 0?
"In that sense, the first decade of the 20th century indicates a period from January 1, 1900 until December 31, 1909."

But the 20th century began in 1901. So surely the first decade of the 20th century is 1901 to 1910.

To put it differently, it's the 191st decade. Now we're in the 201st decade, which goes from 2001 to 2010. Of course, this means that pluralised multiples of 10 aren't calendar decades ... though I suppose you could call the 1990s the 199.9th decade.... -- Smjg 00:43, 15 November 2006 (UTC)

Well I think that a Decade like the ‘Nineties’ is from 1990 to 1999, and do not think that 1990 is still in the 1980s! Websters Twentieth Century Dictionary says of the thirties: the years from thirty through thirtynine (of a century or a person’s age). Similarly the Concise Oxford Dictionary: fifty (in pl) numbers etc, esp years of a century or life, from 50 to 59
 * PS: they both define Decade as ten years, or a group of ten (see below re the Netherlands, ie decade is not used for ten days in English) Hugo999 (talk) 13:22, 6 May 2008 (UTC)

Wikipedia has uncountable numbers of conflicts and errors. Wikipedia does get the page about centuries right:

"According to the Gregorian calendar, the 1st century AD started on January 1, 1 and ended on December 31, 100. The 2nd century started at year 101, the third at 201, etc. The n-th century started/will start on the year 100×n - 99. A century will only include one year, the centennial year, that starts with the century's number (e.g. 1900 is the final year in the 19th century)."

If a century starts with the year 1 then the first and subsequent decades in a century must start with 1. —Preceding unsigned comment added by 69.130.68.20 (talk) 20:46, 31 May 2009 (UTC)


 * You're taking it as a given that language is always consistent. • Either way, reasoning this out is original thought.  We need to find sources. — DragonHawk (talk|hist) 22:36, 31 May 2009 (UTC)

Good sources are on the NASA site and the US Navy Oceanography site. They say: Years of the Gregorian calendar, which is currently in use today, are counted from AD 1. Thus, the 1st century comprised the years AD 1 through AD 100. The second century began with AD 101 and continued through AD 200. By extrapolation we find that the 20th century comprises the years AD 1901-2000. Therefore, the 21st century began with 1 January 2001 and will continue through 31 December 2100.

How simple can it get. If the century and millennium start wit the year 1 so does the decade. —Preceding unsigned comment added by 67.191.99.252 (talk) 01:56, 1 November 2009 (UTC)


 * Your "if the century and millennium start wit the year 1 so does the decade" is patently original thought. You need to cite sources that specifically talk about decades. — Moreover, there is a crucial difference that you neglect: millennia and centuries are typically labeled with ordinal numbers (21st century), while decades are named with prefixes (nineteen-sixties = those years that are of the form nineteen-sixty-something = 1960–1969.) Your argument would have some validity only if decades were indeed numbered ordinally ("197th decade"). That, however, is not done, so your argument is baseless. --Jmk (talk) 09:34, 16 November 2009 (UTC)


 * Additionally, the article is currently making statements that are out of place in an encyclopedia attempting to follow facts. It's saying things like "appropriately numbered," "proper definitions, "many people throughout the world mistake a decade," "common use for this may be for ease of grouping," "technically," "correct usage" and "should be," that are all statements biased in a normative fashion or that come through as original research. The final "although both are in common usage" also seems false considering that 0-9 is by far the more common way to group decades nowadays, as far as making lists or marking events is concerned, at least in regard to the western world and the Gregorian calendar. It's pretty established that a week starts with Sunday, for example. Most almanacs put it first and it's common parlance to say it's first. There's no such "official" way to define a decade, and the more common usage is the 0-9 use, including even special celebrations for dates like the year 2000, which are generally taken divide centuries or millenniums.


 * Let's also keep in mind the calendar was made retrospectively. People didn't start using it right after Christ was supposedly born but 500 to 750 years after that, and the bulk of uses have more to do with relatively recent dates rather than those of the ancient world, so it's usually not a problem if the "first decade" were to appear incomplete when dividing years in the 0-9 fashion. Who is like God? (talk) 03:33, 15 December 2009 (UTC)


 * Section removed, as being mostly absurd. Thanks for pointing it out.  — Arthur Rubin  (talk) 08:10, 15 December 2009 (UTC)


 * According to ISO 8601 the Week starts on Monday, and there is a year 0. —Preceding unsigned comment added by 80.135.180.165 (talk) 04:07, 24 December 2009 (UTC)


 * 0 to 9 is completely false. We start by counting with 1 and end with 10. Furthermore, there is no year zero in the calendar. The first decade AD began with the year 1, and therefore every consecutive decade, century and millennium all began and will forever begin with a year 1. Very simple. —85.178.72.176 (talk) 11:20, 19 December 2009 (UTC)
 * And by the way: This is not original research, because according to ISO 8601:2004 the non-existent "year zero" equals the calendrical year 1 BC. See Year zero. Stop filling Wikipedia with nonsense. —85.178.72.176 (talk) 11:25, 19 December 2009 (UTC)
 * See also Off-by-one_error. —85.178.72.176 (talk) 11:46, 19 December 2009 (UTC)
 * Sorry, but ISO 8601:2004 says nothing about decades. It does not even contain the word "decade". So the standard gives absolutely no support for the "1961–1970" idea; that idea is still original research. — Interestingly, the standard does contain the word "century": on page 13, we learn that the two-digit notation "19" indicates a century, where six digits have been omitted from the date string. In other words, "19" refers to the period from 1900-01-01 to 1999-12-31, since those are the days that give "19" if you omit the last six digits. --Jmk (talk) 06:48, 20 December 2009 (UTC)

I have two issues with the current wording: First, it says "usually" 1-10 and "commonly" 0-9. These statements seem to be at odds, since "usually" and "commonly" have similar meanings in context. The only citations I have found online so far about common and accepted usage would be Dictionary.com, and it indicates no starting date requirement for a decade. (A bit of original thought here: I expect the issue is because of the proximity to the "3rd millennium" debate and the lack of a common term indicating the 2000-2009 interval as one would've had in 1990-1999 in '90s.) Second, I do not see any reputable and widely accepted sources that demand that a decade be counted from any reference point. In fact, decade has a broader meaning than even "10 year interval". See Decade Counter for example. Also, interesting point (and though not an authoritative source) Janet Jackson's album Design of a Decade indicates the 10 year period of 1986-1996. Final point: Wikipedia itself identifies decades in the xxx0-xxx9 interval in List of decades. —Preceding unsigned comment added by 96.49.103.254 (talk) 20:12, 19 December 2009 (UTC)


 * I'd suggest that this whole debate is a straw man argument on both sides. The only consensus definitions for the word decade refer to the interval, not the starting point.  (See citation above.)  Each faction is presuming references to "the decade" refer to the interval with their preferred starting point, and then concludes the other faction is false for being inconsistent with this tacked-on presumption.  As such, I propose the page be revised to include a section indicating "controversy" and that each side of the argument be elaborated upon in its own section without criticism of the other.  The main definition should then refer to only the part for which there is consensus: the definition of an interval of 10 years, without regard to a starting point.  —Preceding unsigned comment added by 96.49.103.254 (talk) 02:42, 20 December 2009 (UTC)


 * I don't think your observation of "straw-men on both sides" is correct. The only folks who cling to "the" decade seem to be the ones who want to use ordinal numbers (first decade, second decade, ..., perhaps then 197th decade?). Their claim that the common "initial digits" definition is somehow "wrong" is based on this assumption of there being "the" decade. — If the common ground is that any consecutive ten years is a decade (I'm fine with that, and it is supported by dictionaries), then obviously e.g. 1960—1969 is a decade and there's nothing wrong with that. We can then proceed to explain how this decade is called (nineteen-sixties), again supported by references. Any claims or insinuations that this common system is somehow "incorrect" are out of place in the article. I have now revised the article accordingly. --Jmk (talk) 04:12, 20 December 2009 (UTC)


 * There's a subtle shift in language there. No one should contest that 1960-1969 is a decade.  The issue that seems to be in contention is what is being referred to when someone refers to the decade, without further qualification.  Your revision skirts the issue by adding qualifiers as in "the decade from 1960 to 1969" followed by a definition of the term "1960s" rather than "the decade" (without qualification).  I propose this revision to enhance neutrality (proposing here, rather than editing directly, since I do not want to perpetuate an edit war): "Although any period of ten years is a decade, a convenient and frequently referenced interval is based on the tens digit of the calendar year, as in using 1960s to represent the decade from 1960 to 1969.  Often, for brevity, only the tens part is mentioned ('60s or sixties), although this may leave it uncertain which century is meant.  These references are frequently used to encapsulate pop culture phenomena that dominated such a decade.  In contrast, some writers like to point out that since the common calendar starts from the year 1, its first full decade contained the years from 1 to 10, the second decade from 11 to 20, and so on.  The interval from 2001 to 2010 would thus be the 201st decade.  However, contrary to practices in referencing centuries, ordinal references to decades are uncommon.  Thus, though unqualified references to "the" decade strictly have at least two interpretations, one is forced to consider whether the context is a common cultural reference, a lesser-common ordinal reference, or some other context.  An example of the latter is the statement, "during his last decade, Mozart explored chromatic harmony to a degree rare at the time," which merely refers to the last 10 years of Mozart's life without regard to which calendar years are encompassed."  —Preceding unsigned comment added by 96.49.103.254 (talk) 23:13, 20 December 2009 (UTC)


 * I like your further revision. In particular, you managed to describe the tens-digits system much more succintly than I did. --Jmk (talk) 08:04, 21 December 2009 (UTC)

The description on this page "Since there is no year zero (0) in either the proleptic Gregorian calendar or Julian calendar, the decades 0s (both BC & AD) comprised of 9 years instead of 10 and similarly the centuries 0s BC & 0s AD comprised of 99 years." seems patently at odds with the description on the century page (http://en.wikipedia.org/wiki/Century): "According to the Gregorian calendar, the 1st century AD/CE started on January 1, 1 and ended on December 31, 100" Furthermore, the reference to dictionary.com (3) supports the notion that "the" (rather than "a") decades start with 1 and end at 0 -- further down the page http://www.websters-online-dictionary.org/definition/decade in the extended definition section it states: "A decade may also be a well-defined historical period of ten years in a dating system. In that sense, the first decade of the 20th century indicates a period from January 1, 1901 until December 31, 1910." Though...that section sources this wiki... —Preceding unsigned comment added by 71.202.135.240 (talk) 19:23, 28 December 2010 (UTC)

Evidently, they really threw a wrench in things when they did not use a year zero. Practically, I think most people would say that anything that took place in 1960 took place in the 1960s. So that would put the decade from January 1, 1960, to December 31, 1969. On this reasoning, it seems that the first centuries CE and BCE get short changed, each by one year. How does one missing year (year 0) equal two? It really isn't missing, you see, because the question really amounts to a counting discrepancy that gets pushed outward toward both ends of the number line -- befuddling plenty of people even tens of centuries. 200.233.63.158 (talk) 11:55, 19 August 2011 (UTC)

The citation removed in this [edit] had nothing to do with Anno Domini, and was merely postulating for a thought experiment that year 1-10 was a decade. The assertion that there even is such a thing as an ordinal decade in the Anno Domini time system is without citation, and is [removed] for that reason. If an actual citation is found for any usage of nth decade with regard to Anno Domini, please undo this edit and provide a source. DrSammyD (talk) 22:18, 1 January 2020 (UTC)

10 days or 10 years?
In the Netherlands, a decade means 10 days, and a decennium means 10 years. The Dutch Wikipage says that a decade meaning 10 years, is in fact wrong. What is the true meaning of ab decade, and who is right? --Robster1983 16:17, 12 June 2007 (UTC)


 * I'm not sure I understand what you mean by "true meaning" when talking about words in different languages. In Norwegian, hat means hatred but in Hungarian, hat is the numeral 6 (wikt:hat). Which one is the true meaning? Perhaps they are both wrong and the true meaning of hat is a covering for the head? If you want to find out what the Dutch word decade means, I guess a Dutch dictionary would be the place to start, not the English Wikipedia. --Jmk (talk) 06:26, 20 December 2009 (UTC)

I agree with Jmk however would like to add the following comment: in French (or in German) a décade means ten days, however may also mean ten years (from English influence). In order to avoid this ambiguity, "décade" has been progressively replaced with "décennie" to describe a ten years period. It seems that there is no equivalent in English to describe a ten days period (?). Yanndudo (talk) 09:48, 6 January 2010 (UTC)

English has the term "fortnight" to cover a 14 day (or night) period, but yeah, no 10 day period. There doesn't need to be a one for one with each language. —  f c s u p e r ( How's That?, That's How! ) (Exclusionistic Immediatist ) — 02:50, 3 March 2010 (UTC)

decade
decade means that somebody is lower in something than somebody else —Preceding unsigned comment added by 24.224.177.110 (talk) 23:29, 31 January 2008 (UTC) That would be decayed, not decade, buddy. Time for some spelling practice! —Preceding unsigned comment added by 118.210.1.42 (talk) 05:57, 2 January 2011 (UTC)

Semi-protect?
Editors (or perhaps one editor) under different IPs keep confusing the article and pushing  the idea that an ordinal reference would be the "proper" way of counting decades, and that e.g. the 1960s would include the year 1970 (definite nonsense), apparently against the consensus reached on this talk page. They do not seem to be interested in joining the discussion here, however. It might be deliberate vandalism, or perhaps simple neglect of common editing practices. Either way, perhaps this article should be semi-protected, to encourage those editors to raise their issues on the talk page instead of edit-warring. --Jmk (talk) 20:54, 1 January 2010 (UTC)

And what's this idea about the 197th decade? Original thought or not, it's a simple fact that nobody who speaks English refers to ANYTHING as "the 197th decade" regardless of when it begins or ends, regardless of whether the subject is informal writing, or the writing of science or history. This is fluff that assumes that "decades" are "wrong" if they include years that end in 0 as the last year of a decade rather than the first. This assumes that somehow, almost everyone who speaks English is doing it "wrong". Utter prescriptivist nonsense, and out of place for Wikipedia. 76.112.248.214 (talk) 03:40, 25 August 2011 (UTC)

"two thousands" ?
'For example, the decade commonly referred to as the "two thousands" ended on December 31, 2009.'

Who calls it this? All I ever see used is "the noughties". Graspee (talk) 08:40, 4 January 2010 (UTC)


 * I don't see it commonly referred to as anything in particular. — Arthur Rubin  (talk) 01:03, 7 January 2010 (UTC)
 * I removed the sentence. It doesn't seem to add anything.  — Arthur Rubin  (talk) 01:23, 7 January 2010 (UTC)

From what I understand, the first decade of 20th Century also had no nickname during that 10 year period. The Aughts was not really adopted until after the decade was over. We are kinda in the same situation now. Who knows what will take hold this time around, as people seem afraid of less common words these days. —  f c s u p e r ( How's That?, That's How! ) (Exclusionistic Immediatist ) — 02:54, 3 March 2010 (UTC)


 * Some people call the decade 2000-2009 the twenty-ohohs. However, the first decade of the 21st century is supposed to be counted as the years 2001 to 2010, and not 2000 to 2009, as a decade always after a multiple of ten years, just as a century shall be counted as a period which ends after a multiple of one hundred years. 212.100.101.104 (talk) 17:14, 1 October 2023 (UTC)

Etymology
The lead paragraph includes:


 * This etymology is sometime confused with the Latin decas (ten) and dies (days), which is not correct.

Problems: 1. The reference is to a French dictionary, which is not appropriate for the etymology of an English word. 2. The French dictionary says the word derives from Latin (which in turn derived from Greek).

dictionary.com says the English word derives from French, via Latin and Greek. So I am changing the lead paragraph to reflect this.UnvoicedConsonant (talk) 19:24, 29 May 2013 (UTC)

turn of decade?
Not a native speaker, I was looking here to understand if 1929-1930 were the turn of the twenties or of the thirties... not found. I think this is much more important than the dispute 0-9 or 1-10. If one speaks of decades, he is not up to mathematical precision, so that it does not really matter; otherwise one tells the exact range explicitly. --Esagherardo (talk) 05:31, 6 October 2015 (UTC)
 * Little late, but here goes. In English, the "turn of" phrasing refers to the period being entered. "The turn of the 20th century" was the transition into said century. Thus, 1929-1930 would be the "turn of the '30s". However, no one actually talks about things like that. We speak of "turn of the century" and "turn of the millennium", but not "turn of the decade". An expression such as "dawn of the '60s" is much more common. (And, in turn, is not used for centuries and millennia.) --Khajidha (talk) 14:52, 9 May 2018 (UTC)

Closely related RFC on "Century" talk page
Please see the discussion at Talk:Century about whether centuries and decades begin in years who's last two digits are "00" or in years who's last two digits are "01". Jc3s5h (talk) 19:37, 31 August 2019 (UTC)

A standard decade in the Gregorian calendar.
Does the 1st decade of the 21st century (as an example) last till 2010 (but not longer), or till 2011 (but not longer)?--130.228.4.61 (talk) 15:53, 15 September 2019 (UTC)
 * I don't consider it used often enough to be well-defined. — Arthur Rubin  (talk) 17:26, 15 September 2019 (UTC)
 * @ 130.228.4.61 Because of differing opinions over when calendar decades, centuries and millennia begin and end, the meaning of expressions such as "first decade", "second decade", and so on is disputed. See the current discussion at Talk:Century Blurryman (talk) 00:14, 16 September 2019 (UTC)
 * By the way, the section ‘0 to 9 or 1 to 0?’ above is related to this.--130.228.4.61 (talk) 14:32, 16 September 2019 (UTC)

Ordinal
To begin with, we need a source that anyone uses "the 202nd decade", etc. Once that is established, we can discuss whether this paragraph gives undue weight to the minority usage. — Arthur Rubin (talk) 17:30, 12 December 2019 (UTC)
 * Agreed, the only time I've ever seen ordinal decades used in any setting outside of a few online forums. I don't think there is any notable debate about it. BlackPointSeaview (talk) 17:37, 12 December 2019 (UTC)
 * Perhaps an article from NASA can be acceptable? The issue is they don't call the period from 2001 to 2010 as the "201st decade", they just call it the "2001-2010" decade so I'm sure if we dig in a little deeper, we can find something. WildEric19 (talk) 19:12, 12 December 2019 (UTC)
 * @Arthur Rubin: So just because the majority of the people is not smart or educated enough to understand a decade ends at the end of the 10th year we should change when a decade ends? I thought the whole point of Wikipedia was to educate as much people as possible for free. We should use the correct information on here, meaning the decade ends 31st of December 2020. LesRoutine (talk) 14:39, 16 December 2019 (UTC)
 * That is absolutely wrong.
 * Centuries
 * The 20th century runs from 1901-2000 (although some conflate it with the second entry, below)
 * The century known as the 1900s runs from 1900-1999
 * Decades
 * The 202nd decade runs from 2011-2020
 * The 2010s runs from 2010-2019
 * The difference is that hardly anyone off Wikipedia uses the "202nd decade", so it shouldn't be given as much space. — Arthur Rubin  (talk) 16:59, 17 December 2019 (UTC)
 * @LesRoutine I strongly agree with Arthur. Apparently claiming other people are "not smart or educated enough" is not the appropriate way to settle a dispute solely because they do not agree with your viewpoint. The 2020s runs from 2020-2029, the 203rd from 2021-2030. Both decades are recognized, but Wikipedia happens to use the popular culture decades - are you going to suggest that we change the system? Do you want us to stop using the "1990s" and use the "200th decade" instead? Most importantly, are you going to claim Wikipedia is wrong? There is no "official way of counting decades", because it can mean any 10 year period. I think you've made a mistake. WildEric19 (talk) 23:31, 17 December 2019 (UTC)

I plan to revert User:Blurryman's restoration of a paragraph beginning "An ordinal decade" because the two sources provided by Blurryman are bilge water. Ordinarily the New York Times is a fine newspaper, but this story, claiming that the Modified Julian date is somehow relate to deciding the start date for decades, is sheer nonsense. Also, the article doesn't make any clear statement about what the right answer is.

The story from the Old Farmer's Almanac contains the statement "According to the contemporary historians of the time, Jesus was born during the 28th year of the reign of the Roman Emperor, Caesar Augustus." Bilge water. The only contemporary historian to mention Jesus was Josephus, and he didn't give a birth date. Such stories are not fit to support anything. Jc3s5h (talk) 01:13, 21 December 2019 (UTC)


 * @Jc3s5h: It’s rather sad to see an experienced editor using such confrontational language. Merry Christmas to you too. Your reading of the articles is rather selective. I’ll bow to your greater knowledge and accept that there are some statements of dubious authenticity in them, but they do not detract from the reporting of the expressions of a preference for a 1-to-0 decade grouping, including Geoff Chester, an astronomer and a public affairs officer at the United States Naval Observatory, and Mordecai-Mark Mac Low, a curator in the department of astrophysics at the American Museum of Natural History who said “There are two different ways to designate decades.” I suspect that the New York Times writer did not attempt to provide a "right answer" because it is clear from the article that there are strongly held views on both sides expressed by authoritative sources. These sources still seem to me to be better than your recent citing of a single author to justify the claim in another paragraph that “a nominal decade is often used to refer not just to a set of ten years but rather to a period of about ten years”. [Italics added.]


 * I also have to say that I am slightly puzzled that you have entirely deleted this text which was part of that which you reinstated on September 30th after the discussion at Talk:Century, and you subsequently slightly amended it on October 9th. What has changed since then? Blurryman (talk) 13:40, 24 December 2019 (UTC)
 * Having re-read the NYT essay (not article), I agree that it has too many errors to be considered a reliable source for the statement that anyone believes the next decade should be 2021–2030. It could be used as justification that someone uses the ordinal decades.  It fails to support the statement in our article.  — Arthur Rubin  (talk) 16:56, 24 December 2019 (UTC)


 * Having reviewed the New York Times article, I concluded that it may deserve mention, but it's not really helpful (or even relveant) to our current situation. Of course, just because such article was posted in an old prestigious journalistic company does not immediately assure everything posted in the article can be trusted right away - editors sometimes make errors, and I've spotted a few of them while reading along. For such, I support Jc3s5h for this time. WildEric19 (talk) 02:14, 26 December 2019 (UTC)

The article as it stands needs a lot of work. In practice no one demarcates decades ordinally in any context; this is not the convention used anywhere in English. This is absolutely WP:UNDUE. Asserting that 'the years 1981–1990 is referred to as the 199th decade' is simply false. No, it is not. The idea is so overwhelmingly negligible it should not be mentioned in the article at all. Literally every single result for 199th Decade is a discussion about how to describe decades and comparing it to the 1980s. Not one use is anyone actually using 199th Decade in this context. Here are some Google Ngrams, 1. the twenties to the nineties, 2. the 20s to the 90s, 3. 1920s to 1990s, and finally (and certainly least), 4. 190th decade to 200th decade. Which it couldn't do at all because there were 'No valid ngrams to plot!'.Frond Dishlock (talk) 03:32, 1 January 2020 (UTC)
 * I don't see this site linked as reference in this talk page yet, so I am just going to link this here. The article brings up both sides of the argument and is the most accurate site I have found online to date on any matter related to how we track the passage of time. aharris206 (talk) 11:39, 01 January 2020 (UTC)
 * The time and date article is literally about the argument being had in this talk. There are still absolutely no references an Nth decade outside of discussions about this exact esoteric subject. 0 usage. If this isn't WP:UNDUE, then WP:UNDUE is completely meaningless. Nth decade has been added to 2 out of 4 bullets in the article. At most it should get 1 mention, and only that there is an argument about it within the confines of this esoteric subject. But it has it's own graph now. Can we remove at least that? DrSammyD (talk) 22:10, 1 January 2020 (UTC)
 * I did a google search for "6th decade of the 20th century", and found 146 hits, of which at least 3 are from scholarly papers. — Arthur Rubin  (talk) 00:42, 2 January 2020 (UTC)
 * And I did a Google search for "the 50s" and "the 1950s" and got 18,300,000 and 54,500,000 hits respectively. 146 is overwhelmingly negligible by comparison, there's also no context for how that phrase is used in those results. They could well be referring to a period dating from 1950 to 1959. Heck, some of them could even be mistakenly talking about the sixties. As the ngrams demonstrated, the usage is so low it doesn't even register to be analysed, which is also the case with "6th decade of the 20th". It's also very relevant that describing a period as the "6th decade of the 20th century" isn't what this article asserts at all. Rather it asserts, falsely, that "the term 196th decade spans the years from 1951 to 1960". This objectively isn't the case. As DrSammyD said, if this isn't WP:UNDUE nothing is.Frond Dishlock (talk) 02:50, 2 January 2020 (UTC)
 * Hilariously, the first article that shows up on google referring to the "6th decade of the 20th century" is actually intending to refer to the 60's in the abstract, which incidentally would be the 7th ordinal decade! The same is true of the congressional report that uses the phrase DrSammyD (talk) 03:05, 2 January 2020 (UTC)
 * haha, yes! I just got an edit conflict when going to point out the same thing, but you beat me to it, just checked that too. Looks like my offhand guess was right, -and from a scholarly paper no less! :DFrond Dishlock (talk) 03:15, 2 January 2020 (UTC)

Well now, looks like we have a definitive answer. Seriously though, the article desperately needs a tidy up, and maybe some sort of future-proofing, since I suspect this is going to come up every decade change. Looking back I see it came up 10 years ago too.Frond Dishlock (talk) 14:49, 3 January 2020 (UTC)
 * Okay, nothing much is moving, so being bold I've made a number of changes using what has been discussed on the talk page, maintaining a NPOV. It seems strange that this should be a divisive issue at all though. Hopefully this satisfies everyone, if there's any specific issues please raise them rather than reverting all of the changes.Frond Dishlock (talk) 03:28, 8 January 2020 (UTC)

Invisible comment
I don't see a consensus in favor of the invisible comment; per Wikipedia guidelines, it should be deleted. I'm not going to do it; fighting for an invisible comment which actually had consensus is one of the things that got me desysoped. — Arthur Rubin (talk) 01:30, 18 December 2019 (UTC)
 * Deleted. — Arthur Rubin (talk) 02:09, 21 December 2019 (UTC)

Edit request.
Request to remove this assertion; "Particularly in the 20th century, a nominal decade is sometimes used to refer not just to a set of ten years but rather to a period of about ten years – for example, the phrase the sixties often refers to events that took place between around 1964 and 1972"

There's no support at the provided citation which supports this. It's a book review, of a book that discusses anecdotes about culture covering a certain era. It isn't an authoritative source on this subject, nor does it support that this is common usage. 'Sometimes' is also arguably WP:WEASEL. The book referred to there states "Personally as someone who lived through the Sixties - a time I count as beginning with the assassination of President John F. Kennedy in 1963 and ending with the resignation of President Richard M. Nixon in 1974 - I have many personal memories of that turbulent, exhilarating, depressing, moving, maddening time that simply do not come together in a tidy package of conclusions", making it clear this is a personal demarcation, rather than an assertion about what the term 'The 60s' means.219.88.68.195 (talk) 03:41, 31 December 2019 (UTC)
 * ✅ Done.  Nixinova   T   C   03:21, 1 January 2020 (UTC)

Terminology: cardinal vs. ordinal (Resolved)
The terms ordinal and cardinal to refer to 1-based vs. 0-based decades don’t seem to be widely used in literature. And they are clearly contradicting the actual meaning of the words ordinal and cardinal: because both common meanings of a decade (i.e. both 0-based decade and 1-based decade: e.g. 2010–2019 vs. 2011–2020) are cardinal decades (the cardinality of the number of years is 10). So is there a widely supported in literature use of these two terms – to denote what would much easier be called 0-based and 1-based decades? cherkash (talk) 16:46, 2 January 2020 (UTC)
 * Well, I'm not sure about cardinal; the commonly used term would be "odometer". But "ordinal" is correct; the difference is between the 2020s and the (rarely used) 203rd decade; no credible person states that the 2020s begins in 2021.  — Arthur Rubin  (talk) 23:51, 2 January 2020 (UTC)
 * I am least worried about the suggested use of the "203rd decade". One doesn't need to go to a precise decade count to know that 1-based decades start with numbers ending in 1 and end with numbers ending in 0. So without referring to the (admittedly silly in everyday use) high decade counts (as in "203rd decade"), one can still talk about decades like 2021–2030 – all you need to know is that they end with the year divisible by 0. So there's nothing about this notion of decades that implies they are ordinal. cherkash (talk) 00:16, 3 January 2020 (UTC)
 * I see no evidence that 1-based decades are used more often than 2-based decades. We might have a couple sentences (I don't think a paragraph is justified) on ordinal decades, in addition to a few sentences on arbitrary decades.  — Arthur Rubin  (talk) 00:19, 3 January 2020 (UTC)
 * This discussion is specifically about cardinal vs. ordinal terminology. I think you digressed. cherkash (talk) 00:52, 3 January 2020 (UTC)
 * Not really. "Ordinal" is the best name for a marginally notable topic.  If there were a name in the literature, we should use that, but the topic doesn't appear enough to have a consistent name.  I was going to suggest "standard" for "0-based" decades, as it's both standard and common, but it's too common to be given a name in the literature.  — Arthur Rubin  (talk) 02:02, 3 January 2020 (UTC)

It would be because 1-based decades are based on demarcating the ordinally numbered centuries. 20th, 21st, etc. 2021-2030 being the 3rd decade of the 21st Century Anno Domini for instance. What else would you call it other than the 3rd decade of the 21st Century? Making them ordinal decades in the defined sense of that word. No one calls them Decade 1, Decade 2. etc after all, and the suggestion of 203rd decade currently present in the article is literally not used by anyone in any context, so that definitely shouldn't be in the article at all. That's less WP:UNDUE, and more just flat out incorrect information/WP:OR. We may not even have to use ordinal or cardinal if we just removed the assertions about decades numbered -1 to -0, and just described the firmly established extant convention for demarcating decades which is used ubiquitously in English. At most a note that when describing the decades of the ordinally numbered centuries in the AD calendar era using ordinal numbering this would technically be periods like 1901-1910 for the first decade of the 20th Century AD and so on, but that this is far more rare.Frond Dishlock (talk) 03:23, 3 January 2020 (UTC)
 * @cherkash on reflection I see your point in regard to cardinal. We're not actually counting anything when we denominate decades by their tens digit. With ordinal though, we do say the first decade or the 21st century. Since no one has shown anything to suggest that counting decades ordinally from the first decade AD is used anywhere, by anyone, in any context, i.e. 196th decade, etc. I have removed that in my latest edit. The form of describing ordinally which decade of the ordinally numbered century it is does appear in references though so I have left this.Frond Dishlock (talk) 03:21, 8 January 2020 (UTC)

There are a few sources that use cardinal vs. ordinal to try to explain which years a decade or century contains. But this is not predominant, and I think those who resort to these words are misusing them and we should not imitate them. Consider the definitions on the Lexico website, which is affiliated with the Oxford English Dictionary: cardinal number and ordinal number. If I conform to these definitions, the whole point of AD notation is to put years in order, so nearly every number in this discussion is an ordinal number, or at least a kissing cousin of an ordinal number.

A valid example of a cardinal number related to calendars would be this sentence from the Vermont Department of Taxes, related to being a Vermont resident for tax purposes: "You maintain a permanent home in Vermont, and you are present in Vermont for more than 183 days of the taxable year" The number 183 is a cardinal number because the order of the days does not matter; it's just a count. Jc3s5h (talk) 20:59, 8 January 2020 (UTC)


 * But I don't see what's wrong with using "cardinal". When you count money, for example, the cashier most likely wouldn't ask you how much you owe in the ordinal form (Your total is 200th and 31st cents.), but they give you the total using cardinal numbers (You owe us $200 and 31 cents). For example, I always use cardinal in my age. I was born in 1939, so that makes me 80 years of age, though I can say I'm in my 81st year but if you want to go down that road, then you'll have to consider someone who is 17 an adult because they're in their 18th year. Here in the US, our drinking age is 21 so does that mean a person who is 20 today can legally purchase alcohol solely because in ordinal terms, he's in his 21st year? I don't think so. Sure you can argue the calendar years are counted ordinally, but not when it comes to cardinal decades, we treat years as 1, 2, 3, 4, 5 as opposed to 1st, 2nd, 3rd, 4th, 5th with the ordinal form. Many of us agree this is 2020, not the 2020th year unless you want to change the system by changing 2020's title to 2020th as with the other years posted here in Wikipedia, but I don't think anyone not even the bureaucrats, are going to agree with that silly idea.


 * The reason why I am opposed to removing the term "cardinal" is because I've seen a reddit post earlier of users being able to tell the difference between a cardinal decade (The 1980s, 1990s, 2000s, 2010s, and 2020s) and an ordinal decade (199th, 200th, 201st, 202nd, and 203rd decades) thanks to us, they read the Wikipedia article of "Decade" something we worked hard for and I'm proud of us for helping remove the confusion. They agree this year is the first year of the new cardinal decade, but the last year of the remaining ordinal decade. I'm afraid if we remove "cardinal", they'll go back to being in a state of confusion. If it's working, don't fix it. As per @Frond Dishlock who suggests that we don't use Decade 1, Decade 2, etc. is because the 2000s is a decade, we don't necessarily have to say "decade" after the 2000s because 2000 to 2009 is still 10 years and qualifies as a "decade". WildEric19 (talk) 21:58, 8 January 2020 (UTC)
 * Cardinal numbers are for counting, ordinals are for ordering. When we are arranging years in to decades, that is fundamentally an ordering operation, so everything is either ordinal, or closely related to ordinal. In the cash register example, it's all about quantity. The cashier doesn't give a whit whether the bills you hand him are in order by their serial numbers. So the amount due is a sort of a cardinal number. (It would be more pure if the amount due didn't require any coins and you paid using only one dollar bills.)
 * As for reddit, if people are picking notation from Wikipedia that isn't found other places, that's bad. We don't do original research here. Jc3s5h (talk) 00:26, 9 January 2020 (UTC)


 * I removed the assertion that this is called 'the cardinal method', as a search of literature, here, it does not appear to be used in this context (where it is used it appears to be methods which are 'cardinal' in the sense 'of chief importance'). Have tried a compromise of describing that the groupings use cardinal numbers in the sense of cardinal numerals, as opposed to and to distinguish the method which describes decades ordinally. I don't think it's strictly necessary to use it, but it may be useful for that reason. The OED at least states in its entry for cardinal number "one of the primitive or ‘natural’ numbers (one, two, three, etc.), as distinguished from the ordinal adj.  numbers (first, second, third, etc.)."Frond Dishlock (talk) 00:38, 9 January 2020 (UTC)

When the terms 'cardinal method' and 'cardinally' were first introduced into the article on December 30 by Nixinova here, it was without providing any edit comment, without any prior discussion, without any attempt at logical justification, and without a single citation for the validity of their use in this context. But no objections were raised until these issues were addressed a little later by the comments above. The majority of views above are against the use of ‘cardinal’ in the article, with only one in support of it.

These 'cardinal' references have since been deleted and reinserted several times by different editors, but on every occasion it has been inserted without citing any sources. In the current version of the article, none of the sources cited at the end of the opening sentence of the "Cardinal decade" section use this word, and Frond Dishlock reported above that a literature search for "the cardinal method" produced a complete blank. Also, the one citation at the end of that section is to a webpage article dated over two weeks after the terms were first inserted into the article! If these terms cannot be shown to have previously been used in authoritative sources, this must surely come under WP:OR and they should not be used in the article.

On another point, I have noted recent changes to the section about "ordinal decade", which was originally used as a term to be distinctively definitive of 1-to-0 decades, on the basis of being the continuously consecutive 10-year groupings starting from the very beginning of the calendar at Year 1; but the present version of the article now also states that the term 'ordinal' can be applied to any decade grouping which can be described as the "Nth decade" in any specified sequence, for example, 'the 2020s are the 3rd decade of the 2000s'. This now makes the term "ordinal decade" useless as a way of distinctively identifying 1-to-0 decades.

Therefore, I think we need to end this time-consuming and ultimately rather pointless argument about what to call the 0-to-9 and 1-to-0 decades, because I do not think it serves any useful purpose, and technical labels will mean little or nothing to most general readers and will not help them in distinguishing between these two decade groupings. So I now agree with cherkash that it would be best to dispense entirely with both of the terms 'cardinal decade' and 'ordinal decade' as not being informative or helpful in identifying these groupings. Since other terms previously used in the article (such as 'common', 'popular', 'strict', and 'technical') have been removed for various reasons, I propose that we now refer to them simply as "0-to-9 decade" and "1-to-0 decade", which are unambiguously clear in meaning and easily understood. - Blurryman (talk) 00:45, 30 January 2020 (UTC)


 * I 100% agree with that, and thank U|Blurryman for that cogent explanation and proposal. HiLo48 (talk) 01:11, 30 January 2020 (UTC)
 * I also agree with as well as with 's analysis above. So Blurryman's attempt at summarizing this discussion with their edit seemed to be on point. On the other hand, this edit by  seems counter-productive: there's only a single contribution of this user to this discussion, and they only argued for reddit's reference to Wiki and how the essentially wrongly-named decades seem to have "remove[d] the confusion" on reddit. Seems quite a weak argument for using terminology that is otherwise not supported by any reliable sources (so essentially being WP:OR) – and definitely a weak reason to be blocking what is a productive edit by Blurryman. cherkash (talk) 01:23, 30 January 2020 (UTC)


 * Okay, we'll go with Blurryman's way. No offense to him, I think he's a great editor and a helper, but the idea of titling the new decades "1-to-0" and "0-to-9" is lame in my personal opinion, but you guys have a fair point of it not really helping so fuck it. WildEric19 (talk) 02:30, 30 January 2020 (UTC)
 * I agree somewhat with Blurryman's comment above, insofar as cardinal and ordinal shouldn't be used in the way they have been, though I don't think the recent edits have been improvements. The terminology of 1-to-0 and 0-to-1, is also unprecedented, and the two different segments may suggest equivalence. I would suggest removing 'ordinal', since the meaning of that word isn't really applicable or related to grouping decades 0 to 1 (and it appears to have only become conflated in discussion by contrast with cardinally numbering), and only using 'cardinal' as a descriptive word for cardinal numbers, i.e. first, second, etc, rather than as a name of a 'method' per se. Also someone has re-introduced that graphic at the bottom with '201st decade' etc, that's already been established at not used by anyone in any context. The sections also omit that any demarcation of decades can be cardinally numbered, as in the first decade of the 1900s. That's just how English works after-all.Frond Dishlock (talk) 03:23, 30 January 2020 (UTC)
 * But ordinal numbers are used for ordering, while cardinal numbers are just used for counting. Jc3s5h (talk) 03:32, 30 January 2020 (UTC)
 * Yeah, darn sorry, I reversed them when I was typing for some reason. I know what they mean, must've been a brainfart, my mistake. So yeah, as someone suggested down the page, it's cardinal I'm talking about removing, and using ordinal only as a descriptive term if it's used, rather than 'naming' a system per se.Frond Dishlock (talk) 01:11, 10 February 2020 (UTC)

Lead section
Is it appropriate that the lead section goes off on a tangent about other words for spans of years with a similar etymological basis? According to MOS:LEAD it should be an introduction to and summary about the most important content of the article. That is, about the subject of the article, and that tangent doesn't seem to be directly about decades per se, and the fact that they also come from Latin is really significant afaics. Seems more suited to see also section, where century and millennium already are linked, though the shorter periods are not very commonly used terms so whether they even need to be is questionable too.Frond Dishlock (talk) 03:42, 3 January 2020 (UTC)

Imprecise or Incorrect Introduction in the Usage Section
The current revision states in the beginning of the Usage section: Any period of ten years is a "decade", and there is no "official" legal nor administrative start or end point. It is immediately followed by two references of which one is dead and not archived, and the other one does not state that there is no legal nor administrative start or end point. Contrarily, an older revision uses the same two references, but states Although any period of 10 years is a decade, which is still arguable, but not a blatant misrepresentation of the references, as of the current state. Therefore, I would suggest to revert it to the aforementioned sentence, or alternatively a better reference should be provided.--2A04:4540:8204:2800:99DE:D6EA:A6FD:A09F (talk) 14:18, 3 January 2020 (UTC)


 * Here is a National Public Radio article which quotes experts who ought to know if there was an official definition of a decade:


 * https://www.npr.org/2019/12/27/791546842/people-cant-even-agree-on-when-the-decade-ends


 * The conclusion is there is no definite answer; it depends on how any individual wants to approach it. Jc3s5h (talk) 15:05, 3 January 2020 (UTC)


 * xkcd hits the nail on the head . --Jmk (talk) 15:36, 3 January 2020 (UTC)


 * Ha! I added that to a section above just a bit before your comment too. Almost needs to be in the article :DFrond Dishlock (talk) 15:45, 3 January 2020 (UTC)


 * This cartoon misrepresents the debate and does not "resolve" anything. Nobody who understands the issue argues that the year 1990 should be included in "the 'eighties". The decade from 1981 to 1990 is described in some other way. Blurryman (talk) 01:10, 4 January 2020 (UTC)


 * Calm down Karen. It's a cartoon. For that matter, nobody that understands the issue would be arguing decades are counted as anything other than 0 to 9.Frond Dishlock (talk) 09:58, 4 January 2020 (UTC)


 * @Frond Dishlock Descending to a schoolyard insult is a clear signal that you have lost that argument. Your other remark is simply wrong, because, although 0-to-9 is one type of decade grouping, it is not the only one which is possible or which is used, as the article makes clear and many other contributors on these pages have pointed out, such as Jc3s5h above. Blurryman (talk) 19:07, 5 January 2020 (UTC)


 * no no, it's a signal that your reaction was hyperbolic. It wasn't an argument; it. was. a. cartoon. 0 -to-9 is in fact the only type of decade grouping used in English by firmly established convention. The fact that you had to say "is described in some other way", is very indicative. Because while the terminology of grouping decades by the tens, the 20s, 30s, 2020s, 1930s, etc, is used, no one in any context demarcates decades using ordinal numbers, there's no articles entitled " 197th Decade in Fashion" because no one, literally no one, demarcates that as a decade in that way. At most, they may contextually describe a decade in relation to a century, i.e. 'The Nth Decade of the Nth Century", but again not as a nominal grouping in of itself, and no one would ever refer to 'The 7th Decade of the 21st Century in Fashion' either. Also that descriptive form isn't even included anywhere in the article at present, which only asserts the preposterous 197th Decade format. Which again, isn't used by anyone as already demonstrated. Saying that it's 'possible' is irrelevant. The article doesn't make anything clear at present, because it's a mess.Frond Dishlock (talk) 23:24, 5 January 2020 (UTC)


 * @Frond Dishlock Your initial remark in your previous comment was offensive, and I note that, far from apologising for it, you have now tried to justify it by offensively characterising my brief and economical rebuttal of the specious argument in the cartoon as "hyperbolic". Also, you have again displayed your disrespectful and condescending attitude with "it. was. a. cartoon", although that didn't previously prevent you from writing that the cartoon "Almost needs to be in the article" and, in another section, labelling it as a "definitive answer". This all suggests that, despite being a cartoon, you think it makes a serious argument, so there is nothing "hyperbolic" about my simply and briefly pointing out that it doesn't. I used the phrase "described in some other way" to keep it short, but here is one example. We do agree upon one thing: the article is presently a mess. Blurryman (talk) 19:56, 6 January 2020 (UTC)


 * Oh pish posh. Your 'rebuttal' was misplaced. My use of 'ha!' and 'seriously though' refute your argument. Don't be so po-faced. Also the decades in question at that link are not referred to with any specific name or designation, the span is merely indicated in the form of 1901-1910, so that supports my position. The same as any group of ten years is a decade. This is merely a result of their data set starting from -1999 to -1900. The cartoon isn't specious, you're just failing to appreciate the point being made.Frond Dishlock (talk) 22:00, 7 January 2020 (UTC)


 * I'm not wasting any more of my time on someone who cannot conduct a civil conversation. WP:EQ. Blurryman (talk) 00:20, 8 January 2020 (UTC)


 * Alright, sorry. Mea culpa. I can see how that may have come across as brusque on reflection, this was not intended, but rather as good-natured banter. This may be a cultural difference, I would ask you to WP:AGF and I will do the same.Frond Dishlock (talk) 03:10, 8 January 2020 (UTC)


 * @Frond Dishlock Thank you for that generous gesture. Apology accepted. Let's move on. Blurryman (talk) 00:09, 10 January 2020 (UTC)

Research supporting the Ordinal viewpoint is required
If anyone may help me look for a source that complies with the reliable sources policy that would be appreciative. To begin, I don't know if "nth decade of the century" is appropriate because I have never heard an author use such a title, and for this more research is required according to Wikipedia's verification policy. We don't do original research here, meaning we came up with the name without backing a credible source. The ordinal perspective section needs a citation that supports our claim. It's like going to court, you need evidence. Don't expect the judge will believe in anything you say without representing evidence first. If you have a question or would to discuss this, I'm open for comments on certain time (I will be getting surgery on Wednesday so I'll be offline after the operation for healing) I'm looking for someone who could help me look for a source, I thank you in advance. WildEric19 (talk) 21:50, 18 January 2020 (UTC)
 * The good news is I found a CNN article to support the ordinal form of decades, but the issue is it doesn't titled ordinal decades as "nth decade of the mth century", but as "nth decade". Here is the source, but more research can be helpful. WildEric19 (talk) 22:04, 18 January 2020 (UTC)
 * I did a search a few sections up for ""6th decade of the 20th century", and it came up with a 146 hits, at least 3 from scholarly papers. Another editor noted it was used in those papers for a decade near the 1960s, rather than the correct 1950s.  So, it shouldn't be used as a source in this article....  — Arthur Rubin  (talk) 01:28, 19 January 2020 (UTC)
 * The good news is I was able to find this to support a case of the "203rd decade". Now, we need confirmation that the "3rd decade of the 21st century" exists. Update: Due to a dispute, I restored the old verison and removed the new diffs. WildEric19 (talk) 21:19, 22 January 2020 (UTC)
 * The problem is: either we leave the current version, or we remove the sentence altogether. The reason for that is that any approach, including the cardinal method, will have all decades numbered so that any decade will be the "Nth decade" in that method. For example, the 1st decade in the cardinal method starts in 1BC. On the other hand, Anno Domini centuries are always numbered ordinally, so that when we say 1st century BC, there is no ambiguity. So, if you're not happy with the sources supporting this comment on format, I propose we remove it altogether. But, personally, I think that we should keep it, given that it's not hard to find sources where the format "Nth decade of the Mth century" is adopted, and, furthermore, the comment is on how the method works instead of how it is used. The claim is that all ordinal decades can be formatted in this way - not that they are. O̲L̲D̲S̲T̲O̲N̲E̲  J̅A̅M̅E̅S̅?  21:49, 22 January 2020 (UTC)
 * I want to be very clear why your diff was reverted. It's because your statement of centuries always (Which I think by the way is a weasel word) being counted ordinally is not correct according to the general usage on our century article. If we were to go with this title, it would be considered original research which we don't do here plus violation of the verification policy (which state all claims must be accompained with a source - which we at this moment, don't have and this is the issue we're currently discussing). For your convenience, I restored the old version, but it's temporarily. If we are unable to find a source, then we have no choice but to remove it. This is NOT a debate to when centuries/decades begin or end, the issue is the lack of reliable sources. I ask you please give me a hand searching for a source, Rubin was able to find one, but as he pointed out it's not a best citation and shouldn't be used. I'm still looking. WildEric19 (talk) 22:16, 22 January 2020 (UTC)
 * I see, yeah, that statement is probably incorrect, then. I've edited the article so that the phrase in question now says 'Nth decade since the start of the common era'; I think this statement is pretty uncontroversial and would probably constitute WP:BLUE? It's pretty much common knowledge that Anno Domini ordinal decades start counting ordinally since the start of the common era, which is implied by the fact that, for example, the next decade starts in 2021, for which there are plenty of sources. This fact was also demonstrated in the visual aid table, which has since been removed for some reason? I think it is very helpful to leave this table there. Anyway, I hope you don't mind this style of editing, whereby we both make edits which take into account feedback given here on the talk page without first discussing the edits and stop at the first revert. I think it's just quicker and more efficient this way. What do you say? O̲L̲D̲S̲T̲O̲N̲E̲  J̅A̅M̅E̅S̅?  01:06, 23 January 2020 (UTC)

the Time & Date source you added to this thread at 21:19, 22 January 2020 (UTC) isn't a suitable source, because it says 'the upcoming decade is technically the 203rd decade, but we call it the twenties."' I interpret that to mean that the term "203rd decade" is nomenclature used only within the discussion within that web page, and everybody else calls it "the twenties". So rather than supporting the point of view that "203rd decade" is proper usage, it really supports the opposite view.

I see two problems with interpreting "Nth decade of the Mth century" as the period MN1 through M(N+1)0. First, Mth century might be the Mth century in ISO 8601 numbering or astronomical year numbering, in which case it is the period MN0 through MN9. Or, the author might write "Nth decade of the Mth century AD", but when informed this means period MN1 through M(N+1)0, might tell the person making this point to stuff his pedantry __ ___ ___, it means period MN0 through MN9, all arguments to the contrary be damned.

After all, English is full of logical inconsistencies, and it is not the role of Wikipedia to enforce logical consistency if the general public rejects it (at least in the arena of English usage). Jc3s5h (talk) 01:18, 23 January 2020 (UTC)
 * Agreed, I've already removed this wording and replaced it with a more accurate statement. O̲L̲D̲S̲T̲O̲N̲E̲  J̅A̅M̅E̅S̅?  01:28, 23 January 2020 (UTC)


 * Thanks for sorting things out @Jc3s5h. And I'm glad @Oldstone James and I can agree on something together and not argue :-). WildEric19 (talk) 02:08, 23 January 2020 (UTC)


 * Ha, you threw a quick glance at my editing history, didn't you ;) I fully share your sentiment. I'm so sick of the everlasting arguments and conflicts here on Wikipedia that I'm really glad we could collaborate productively on this occasion. Thanks for being agreeable and not rushing to revert my edits straight away despite disagreeing with them; this is overwhelmingly appreciated. Also, not to spoil the climate, but what were your reasons for removing the visual aid? I thought it was really helpful and intuitive. O̲L̲D̲S̲T̲O̲N̲E̲  J̅A̅M̅E̅S̅?  02:42, 23 January 2020 (UTC)


 * Just for the record, Jc3s5h's explanation cannot be said any better than why adding the "3rd decade of the 21st century" should not be used. When I tried to add the difference between an ordinal or cardinal decade, I lost because Wikipedia's NOR policy blocked me from moving forward with those labels. This policy also applies to describing a decade's title. For such, WP:Verifiability requires a reliable source, using "nth decade of the century", be provided since it's not heard of and raises question whether such statement is even used. So please, help us find a reliable, valid source if you possibly can.


 * FYI, I don't see ANY good reason why we should include 2 titles for 1-to-0 decades, it will create confusion so it's best we stick with only ONE title and it's "nth decade since the start of the Common Era", because we found a reliable source for that and it complies with Wikipedia's verification policy where all non-obvious edits should be cited (Plus we don't call the 1980s the "ninth decade of the 1900s" so what's the point in having that for the 1-to-0 viewpoint?). The new edits violate the No Original Research policy since they're left unsourced. The reason why no reliable source uses the title "nth decade of the century" is because that viewpoint is almost never used as stated in the section. I want to take this time to clarify to Blurryman and Cherkash that the problem is NOT the title, it's the lack of reliable sources. We tried everything we can to find a source, but we couldn't find anyone. If you can find one, please provide it here for approval. A year ago, in 2019, I asked editors if they can help me with the sourcing, no one was able to find anything. WildEric19 (talk) 02:43, 5 February 2020 (UTC)


 * For the record, when I added the phrasing "2nd decade of 20st century" I did so as deviation from the previous form ("202nd century") to satisfy the critism previously expressed about this higher-number counting of decades having no known usage in popular media or trusted sources. I thought it strange to want a source to validate that one can count a thing beyond a certain number. (If we establish "5th decade" as valid, why need additional sources before counting beyond 9?) Nonetheless, while I disagreed with this argument, I did agree that it is extremely rare (if found at all) for authors to refer to decades after the first century by their full ordinal name. I don't think any scholar, news reporter, or other writer would with straight-face refer to 1885 as being "in the 189th decade". By popular account, using the cardinal form of 1880s is the most common. But within the ordinal school, one would likely hear "late 19th century", or more precisely "9th decade of the 19th century". Presumably because terms like "19th century" have a familiar ring and connotation and will be more widely and/or more quickly understood. And indeed this phrasing can be found in millions of works as demonstrated with a simple online search, compared to only a few dozen for the full ordinal form (where most debate the subject about decades itself). If our objective was to reflect the more common form (within the ordinal school), should the "decade of century" form not be preferred, given its abundance of examples? --Krinkle (talk) 23:07, 9 February 2020 (UTC)

Someone re-introduced this, -can we get rid of it? As before it erroneously introduces the idea that the form 201st decade, 202nd decade, etc, is used. Whereas it's been pretty conclusively shown that no one does or ever has used that form, and no evidence to the contrary. As well as the assertion that it's used in that section " the period from 2021 to 2030 is the "203rd decade"" -where 1-to-0 decades are used they are always referred to in relation to an ordinally numbered century, e.g. the 1st decade of the 20th Century. Frond Dishlock (talk) 01:14, 10 February 2020 (UTC)


 * I don't see any problem with this, Jc3s5h provided a detailed explanation earlier of why it's not a good addition. I personally think it's also a bad idea since there is an ongoing debate whether centuries run from 01-to-00 or 00-to-99. The first decade of the 20th century may mean 1901 to 1910 or 1900 to 1909 depending on whether you're going with the strict or general viewpoint. We had a similar discussion like this a long time ago, you can read it here. This here is NOT the place to argue that the only correct way to count centuries is from 1 to 0, because that should be taken to the century talk page. WildEric19 (talk) 14:25, 10 February 2020 (UTC)
 * User:WildEric19 do not misrepresent the views of timeanddate.com in their article When Does the New Decade Start?. That article states 'For example, we say “the eighties” instead of “the 199th decade.”' Jc3s5h (talk) 15:11, 10 February 2020 (UTC)


 * @Jc3s5h I'm sorry, but after scrolling up, I failed to see what you said earlier. I guess timeanddate.com isn't a good selection after all. At this time, I'll be busy so I'll respond sometime later. WildEric19 (talk) 15:20, 10 February 2020 (UTC)
 * First off, it's not okay to delete a section someone else created and move their comment. Secondly, this has already been addressed. No one uses or has ever used that form of referring to decades, this has been shown conclusively. The only reference referred to explicitly states that we don't use it. It should not have been re-introduced.Frond Dishlock (talk) 10:53, 14 February 2020 (UTC)
 * The irony of adding this "Note before editing section: Please do NOT add "nth decade of the century" unless you're able to find a reliable source USING that title. Unsourced material or use of poor sources is subject to challengement or removal. Thank you." as a note on the section is rather large. No sources support the current version of that section, and quite the contrary demonstrate that it is wrong. It has already been demonstrated that the only context decades are applied is as divisions of centuries. At this point, and with the re-insertion of unsupported and demonstrably incorrect information I think we should be proposing to delete all references to the '1-to-0' decades entirely unless the use can be properly cited (and while I understand how the descriptions were reached here, the 0-to-1/1-to-0 terminology itself is arguably OR). As it stands the graphic and assertion of that decades are numbered in of themselves e.g. "203rd decade" etc, is false and needs to be removed asap. Even the citation there explicitly states that we don't call decades that. I think a month is a reasonable amount of time to give this. Also -'challengement' isn't a word.Frond Dishlock (talk) 03:24, 18 February 2020 (UTC)


 * After reviewing timeanddate.com, I agree it was a poor use of source. I'll allow 30 days for a reliable source to be added. If no source is added, then I'll HAVE remove it as it will violate WP:NOR. Due to the fact that is barley used, I think we should just get rid of the 1-to-0 decade and leave the 0-to-9 usage. It's not Wikipedia's job to keep something the general public does not give any attention to. If anything, we'll just leave the NASA article without using either 'nth decade of the century' or 'nth decade since the start of the common era' to represent that the 1-to-0 decades are also valid.


 * I also want to let others know WHY "nth decade of the century" isn't a good selection. According to our Century article: "Although a century can mean any arbitrary period of 100 years, there are two viewpoints on the nature of standard centuries. One is based on strict construction, while the other is based on popular perspective (general usage). According to the strict construction of the Gregorian calendar, the 1st century AD began with 1 AD and ended with 100 AD, with the same pattern continuing onward. In this model, the n-th century started/will start on the year (100 × n) − 99 and ends in 100 × n. Because of this, a century will only include one year, the centennial year, that starts with the century's number (e.g. 1900 was the last year of the 19th century). In general usage, centuries are built by grouping years based on their shared digits. In this model, the 'n' -th century started/will start on the year (100 x n) - 100 and ends in (100 x n) - 1. For example, the 20th century is generally regarded as from 1900 to 1999, inclusive. This is sometimes known as the odometer effect. The astronomical year numbering and ISO 8601 systems both contain a year zero, so the first century begins with the year zero, rather than the year one.

In a summary, if we were to use "third decade of the 21st century", it would question whether that would be 2021-2030 (the strict viewpoint) or 2020-2029 (the general viewpoint) because centuries are disputed and this has been going on for decades. Wikipedia's job is to accept BOTH viewpoints as correct if they're accompanied by a source, and they are. WildEric19 (talk) 18:29, 18 February 2020 (UTC)


 * I am unable to respond at any person who wishes to comment back. I am having feeling very ill and will be taking a trip to my PCP soon. Sorry for the inconvenience. If you wish to comment, please do so but wait for my return. WildEric19 (talk) 19:31, 18 February 2020 (UTC)


 * In the light of Krinkle, above, having unearthed "millions" of sources illustrating the use of the "decade of century" terminology, I now support his proposal to use that in the article, which has also been supported by several other editors in this and other discussions. The sources found by Krinkle include The British Library, The British Museum, Christie’s of London, the Oxford University Press, and the State Hermitage Museum, St Petersburg, which I presume satisfy the demand for reliable sources. I have also found in the entry for "decade" in my 1979 copy of the "Complete Oxford English Dictionary" its citation of “1837 HALLAM Hist. Lit. I. i. 19 In the second decad [sic] of the 12th. Cent.” I therefore propose changing the wording in that part of the article, subject to comments, thus:
 * A rarer approach is to group years from a year ending in a 1 to a year ending in a 0, with the years 1-10 described as "the 1st decade", years 11-20 "the 2nd decade", and so on, with later decades more usually described as 'the Nth decade of the Mth century' (using the “strict” interpretation of ‘century’); for example, the period from 1801 to 1810 is described as "the 1st decade of the 19th century".[INSERT SOURCES] Such a decade may also be referred to explicitly as, for example, "2021–2030".[EXISTING SOURCE].
 * - Blurryman (talk) 00:59, 19 February 2020 (UTC)
 * The problem with relying on the quantity of search engine results is we don't know exactly what each source meant by phrases such as "8th decade of the 19th century". Those who thought the 19th century spanned 1800 through 1899 thought it meant 1870 through 1879, while those who thought the century was 1801 through 1900 thought it meant 1801 through 1880. And then there are those who were being deliberately vague, and weren't sure if whatever they were writing about included 1800 or 1880. Jc3s5h (talk) 01:30, 19 February 2020 (UTC)
 * I agree with Blurryman's proposal above. -I don't see a problem with centuries being demarcated both with ordinal numbers within the AD calendar era (which is what that form refers to by convention), and also by numbered groupings as in the 1800s, 1900s. It's not so complicated to have two different forms, even if they do, or maybe especially because they do, so nearly overlap. It just happens that in English the overwhelming usage for decades is to demarcate the latter rather than the former, unless someone wants to be oddly specific for some reason, then it's more a matter of just describing something in plain English -the same as you'd describe the 'first decade' of any period long enough to divide into decades, rather than de facto nominal decades (by which I mean we don't just use that as numbering but to 'name' a decade, such as 'The 60s'). Given the overwhelming ubiquity of usage though we should give more weight to that form (the 1960s/'60s, 1970s/'70s, etc). There's an interesting article here talking about style of Sixties vs sixties as well, that is sort of tangentially related.Frond Dishlock (talk) 23:08, 19 February 2020 (UTC)
 * Frond, I disagree about leaving general centuries as "1800s, 1900s, 2000s," because the general viewpoint conflates them with the "19th, 20th, and 21st centuries", and the ordinal-titled centuries are more popularly-used. WildEric19 (talk) 02:46, 20 February 2020 (UTC)
 * I didn't say anything that equates to "leaving general centuries as "1800s, 1900s, 2000s,"", though I'd say that the ordinal-titled centuries being more popularly used is debatable, -they're much the same in terms of usage (this isn't the place to do that of course). That's beside the point though, since the actually fact is that in terms of decades it is centuries in that context which are demarcated. This has already been demonstrated.Frond Dishlock (talk) 02:23, 22 February 2020 (UTC)
 * I made changes that I hope can settle this once and for all. I carefully edited to satisfy Frond and Blurryman's side, but at the same time looking for a way for Jc3s5h and I's viewpoint to be combined. The only part where I disagree is using "successive" as ISO counts differently. Is this agreeable to everyone? We all have important things running in our lives and I think it's time we moved on. WildEric19 (talk) 05:19, 25 February 2020 (UTC)
 * That's all looking pretty acceptable at the moment afaics. Maybe we should put a note on the article asking that significant changes be discussed here for consensus before being made? -And everyone meet back here a few months before 2030 to argue it out with a new generation of opposing pedants POV championing both valid positions respectively as the only 'correct' form :'DFrond Dishlock (talk) 22:38, 25 February 2020 (UTC)
 * I'm confused with what you're trying to say. Can you clarify please? WildEric19 (talk) 03:35, 26 February 2020 (UTC)
 * I'm not sure what bit you were confused by. I said it all looked pretty acceptable. -The second bit was just an aside that the argument will probably come up again in ten years when people start arguing about when the next lot of references to 'the new decade' start. Iirc, there were a ton of edits on this article back around 2009-to-2010 change-over as well.Frond Dishlock (talk) 01:15, 27 February 2020 (UTC)
 * Still, I'm not sure what you meant by "And everyone meet back here a few months before 2030 to argue it out with a new generation of opposing pedants POV championing both valid positions respectively as the only 'correct' form" WildEric19 (talk) 23:20, 27 February 2020 (UTC)
 * I just explained that; I'm half-jokingly making a point that similar arguments will be had next time a new decade is coming up. It was just an aside.Frond Dishlock (talk) 23:02, 2 March 2020 (UTC)
 * Very well. I hope I can make it to 90 because I became 80 in 2019, so I hope I can make it to help you guys in the next decade debate. Haha ;-). As someone who is 81, I am still active and eating what my doctor advised me to consume. WildEric19 (talk) 01:18, 27 March 2020 (UTC)

Ordinal and cardinal methods (resolved)
While the previous discussion has reached a consensus regarding the names of the methods, I am not happy with the fact that the intuition behind the methods isn't mentioned at all. That is, even though it may be wrong to describe both types of grouping using ordinal/cardinal terminology, it is clear that the reason that these two methods are so prevalent is that they rely on ordinal vs cardinal intuition. However, this intuition is not mentioned, and to someone unfamiliar with how decades are normally grouped, it might seem like both methods are totally arbitrary. I suggest that we at least add introductory sentences to sections "0-to-9 decade" and "1-to-0 decade" explaining that the motivation behind each classification is an ordinal/cardinal interpretation of Anno Domini. O̲L̲D̲S̲T̲O̲N̲E̲ J̅A̅M̅E̅S̅  17:30, 30 January 2020 (UTC)
 * I have edited in one example of what such introductory sentences might look like. Let me know if you have any objections to this edit. O̲L̲D̲S̲T̲O̲N̲E̲  J̅A̅M̅E̅S̅  17:43, 30 January 2020 (UTC)
 * I agree it would be nice to mention the rational behind the groupings. But I don't think we should use the term "cardinal" at all. "Ordinal" could be used for both methods, so we probably shouldn't use "ordinal" either.
 * The definitions in the online dictionaries aren't to my liking, so I'll quote American Heritage Dictionary 3rd ed. (unabridged, 1992).
 * cardinal number n. A number, such as 3 or 11 or 412, used in counting to indicate quantity but not order.
 * ordinal number n. A number indicating order in a series or order. The ordinal numbers are first (1st), second (2nd), third (3rd), and so on.
 * So what if a number doesn't fully satisfy either definition? For example, 1992 indicates order; it's the year after 1991 and before 1993. So it isn't a quantity, order is important. It isn't just a count. For example the sentence "in 2007, Smallville had 97 days with detectable precipitation", 97 is clearly a cardinal number, but 2007 is more like an ordinal number, even though it isn't written as "2007th".
 * Another consideration is that if you attempt to use more rigorous definitions of cardinal number and ordinal number you run into the mind-numbing definitions used in set theory. These definitions weren't invented until the late 1800s. To the best of my knowledge, these modern definitions aren't taught outside of university math departments. The aren't even taught to people who use heavy-duty math for practical purposes, like engineers and physicists, much less the general pubic.
 * The incomprehensibility of the set theory definitions is so bad that Wikipedia has created separate articles, cardinal numeral and ordinal numeral, for the meanings in everyday speech, as taught in elementary and middle schools. Jc3s5h (talk) 18:15, 30 January 2020 (UTC)
 * Well, while the numbers used by the 0-9 method may be ordinal, the interpretation of Anno domini is undoubtedly cardinal. That is, the fact that the year is 1992 represents the fact that 1992 whole years have passed since the start of Anno domini (in the 0-9 method). So the method here goes something like this:
 * Using cardinal numbers, specify the number of whole years which have passed since the start of Anno domini
 * Then take this cardinal number to indicate the ordinal number of some given year
 * So I don't see the issue in saying the the interpretation of Anno domini here is cardinal. O̲L̲D̲S̲T̲O̲N̲E̲  J̅A̅M̅E̅S̅  18:35, 30 January 2020 (UTC)
 * The definition I gave from American Heritage Dictionary is similar to what you find in other dictionaries. It states or implies an ordinal number in the English language has several properties.
 * It indicates order.
 * It is an integer greater or equal to 1.
 * It ends in the letters "st", "nd", "rd", or "th".
 * A cardinal is not used for ordering, only for counting.
 * So we could make a statement "The period 1 January AD 1 to and including 31 December 1992 comprises 1992 years." The second instance of 1992 is pretty clearly a cardinal number. For the first instance of 1992, order is clearly important. Some people might say that instance is an ordinal number, others might say it is neither ordinal nor cardinal. Jc3s5h (talk) 18:47, 30 January 2020 (UTC)
 * I don't think we're on the same page here. I agree that in your sentence the first instance of 1992 is not cardinal. I've actually expressed my agreement with this in my previous comment. But, if you look at the method that I laid out, the first step of the method involves counting the number of years passed since Anno Domini, which would clearly end up giving a cardinal number, as you have explained in your comment. Only after obtaining this cardinal number do we convert it into an ordinal number (or a neither-ordinal-nor-cardinal number - it doesn't matter). So I don't think it would be controversial to say that the interpretation of Anno domini is cardinal, given that the first step of the 0-9 method obtains a cardinal number based on the Anno domini convention. O̲L̲D̲S̲T̲O̲N̲E̲  J̅A̅M̅E̅S̅  19:40, 30 January 2020 (UTC)
 * It seems to me, if I write AD 2020, I am using that notation because I want the position of the year in the series of years that native English-speakers use for nearly all purposes. The AD notation inherently puts years in order. Introducing the term "cardinal" just so we can make a somewhat convoluted explanation, where the reader has to draw diagrams to tell which number is cardinal and which isn't, isn't helpful. Jc3s5h (talk) 20:15, 30 January 2020 (UTC)
 * I still don't think you understand what I'm saying. Let me give you another example, which should hopefully clear things up. Imagine the prices of various items were stored in an ordered set, sorted by size. Within this set, £5 might come after £4, which itself might come after £3. It's pretty clear that all of the values £5, £4, and £3 are cardinal. However, within the set, they are arranged in an ordered manner, so that when we refer to "the £4 item", we are referring to the item which comes after "the £3 item" and before "the £5 item". And it's exactly the same with the "cardinal decade": originally, the years are sorted by how many years after Anno Domini they come after (which is a cardinal number), and then are labelled by this number of years - the same way that the items in my example are labelled by their price. Therefore, when we say, "year 2020", we intuitively think of 2020 as the number of years which must have passed since year 0 - NOT as the position of the year since the 1st year, which would be the "ordinal approach".
 * All of this is intuitive and doesn't require the reader to draw any diagrams; it is simply a description of the intuition behind both approaches that pretty much relies on. You're right that, when you write AD 2020, you're referring to the position of the year in a series; however, the "cardinal approach" treats the number "2020" not as the position in a series but as the number of years passed since Anno Domini. Does this make sense? O̲L̲D̲S̲T̲O̲N̲E̲  J̅A̅M̅E̅S̅  21:33, 30 January 2020 (UTC)


 * In the expression "year 2020", "2020" is undoubtedly an ordinal number: it indicates the order of the given year in a series. In the same way as e.g. instead of "the second task" (out of whatever ordered set of tasks you may consider in a given context) you can say "task number two" or even "task two" – in all these cases the functional use of the word "two" is an ordinal numeral. Interpreting "2020" in "year 2020" expression as indicating cardinality of a set of years is clearly a frivolous interpretation. And so even when shortened to just "2020" as in, e.g., "this happened in 2020", what is clearly meant is "this happened in the year 2020", where "2020" is again semantically an ordinal number. cherkash (talk) 01:10, 31 January 2020 (UTC)


 * Even though I don't like the new "terminologies", I can let this go. "0-to-9" and "1-to-0" it is then. WildEric19 (talk) 20:56, 7 February 2020 (UTC)

The problematic "anno Domini-before Christ convention"
The article had a very strange construction that I found jarring, reading: "There are two methods of demarcating calendar decades of the years of the anno Domini-before Christ convention".

This was jarring for several reasons, not the least of which is that the casual reader would struggle with knowing what the "anno Domini-before Christ convention" is (WP:PLA). It's also strange to see the word "Christ" appear in a subject about the word "decade" and dragging religion into this article certainly isn't needed. I have no idea why AD and BC were spelled out this way, but it isn't necessary and only confuses things.

Changing it to "common era" meets the manual of style on a number of respects. 1) It's a common term that is easily understood.  2) It is consistent with the rest of the article, such as where the article says: each decade is described as the Nth decade since the start of the common era, which adheres to WP:ERA's guideline to keep the article consistent. 3) "Common era" is a better understood concept than whatever "anno Domini-before Christ convention" is supposed to mean.

Apparently, there was disagreement about "common era", for reasons that weren't terribly convincing. As there was no consistency before my edit, it's hard to argue that consensus was needed to change something that didn't exist. Be that as it may, I changed it to "Gregorian calendar" to avoid the whole WP:ERA thing and because it's arguably better as not only is it a better understood and defined term than whatever "anno Domini-before Christ convention" is, but is also consistent with the articles Century and Millennium, which also use "Gregorian calendar" throughout. It also accounts for BCE years.

I'm going to propose the term "anno Domini-before Christ convention" be replaced with either "common era" or "Gregorian calendar". Don't care which. 73.254.89.77 (talk) 18:52, 18 February 2020 (UTC)
 * Changing to Common era requires consensus, per WP:ERA. However, I'm not sure about Gregorian calendar; some decades we talk about are in the Julian calendar. — Arthur Rubin  (talk) 19:48, 18 February 2020 (UTC)
 * As stated above, "common era" is already used in the article. There was no consistency and WP:ERA calls for consistency first and foremost.  This was the only place where this term "anno Domini-before Christ convention" is used -- as near as I can tell -- anywhere on Wikipedia.  As for the Julian calendar, a shift of 13 days doesn't really factor into a decade and is a bit.... shall we say... pedantic?  This is why it doesn't really factor in here or in Century or Millennium or anywhere else that's discussing these concepts. I'd much prefer the clarity and accessibility over inventing new terms to cover this.  73.254.89.77 (talk) 20:04, 18 February 2020 (UTC)
 * Looking through the article history for the past 1000 edits, it appears the article has not had a stable version for a decade or more. So the advice at WP:ERA about retaining an existing established style does not apply. The English Wikipedia Manual of Style does not recognize "common era" as inherently more neutral than "anno Domini".
 * "Gregorian calendar" is absolutely unacceptable in this context because it could imply that decades did not exist before 1582, or that decades should be counted from some some important adoption date, such as 15 October 1582 or 14 September 1752. Jc3s5h (talk) 19:53, 18 February, 244th year of independence of the United States (UT)
 * That's, I'm sorry, nonsense and doesn't jibe with MOS:JG either. I mean, I have absolutely no idea what to say to that argument. 73.254.89.77 (talk) 20:08, 18 February 2020 (UTC)
 * But let me ask you something: Why "anno Domini" and not "AD"?  What does spelling it out bring other than to confuse people?  People know "AD".  People know "BC".   People don't say "anno Domini".  73.254.89.77 (talk) 20:11, 18 February 2020 (UTC)
 * One of the passages 73.254.89.77 is concerned about is "There are two methods of demarcating calendar decades of the years of the anno Domini-before Christ convention". If we change this to "There are two methods of demarcating calendar decades of the years of the Gregorian calendar" it would mean nothing we write applies before 1583, and that the article just isn't addressing how people write about anything that happened before 1583. Jc3s5h (talk) 20:28, 18 February 2020 (UTC)
 * Thank you for restating my own position to me. It is still nonsense.  The Gregorian calendar is perfectly capable of expressing dates, decades, centuries, and millennia before 1583.  This is a silly argument.  Besides, we're talking on a 10-year macro level here.   A 13-day offset between two otherwise (nearly) identical calendar systems really doesn't change the underlying concept of 10 years.  However, if this is the hang-up here, I'm willing to go with the "years of the Julian and Gregorian calendars".  73.254.89.77 (talk) 20:34, 18 February 2020 (UTC)
 * "Anno Domini-before Christ convention" is a name phrase to describe the year numbering system. The Julian and Gregorian calendars commonly use this system, but sometimes use other year numbering systems. The Gregorian calendar is used with ISO 8601, which numbers the years ...&minus;0001, 0000, 0001.... Both Gregorian and Julian calendars are used with Astronomical year numbering, which numbers the years ...&minus;1, 0, 1.... During AD 1 the Romans, who were using the Julian calendar, called it the year of the consulship of Caesar and Paullus. Jc3s5h (talk) 21:10, 18 February 2020 (UTC) Modified 21:03, 18 February 2020 due to nitpicking by 73.254.89.77.
 * "Anno Domini-before Christ convention" is a name for the year numbering system. Citation needed.  As near as I can tell, this is a term you invented.  I can find no significant references to this term -- other than this article -- anywhere.  Google comes up with all of 4 hits on it, 3 of which are mirrors of this article.  It's a clear neologism.  ... and what does any of this have to do with the content of the article text in its context of year demarcation?  Let's keep focused on what's in front of us, which are the two paragraphs that follow this line in the article, not a treatise on picayune calendar novelties.  73.254.89.77 (talk) 21:25, 18 February 2020 (UTC)
 * It has to do with decade demarcation because if we use astronomical year numbering or ISO 8601, common usage and the rules of the number system both tend to favor 0 to 9 decades. Therefore, calendars that can be used with year numbering systems that do, or do not, have a year 0 should not be used to indicate which of those numbering systems is in use. Jc3s5h (talk) 22:07, 18 February 2020 (UTC)
 * I'm not going to get into that debate here. You can fight that up above in that section.  However, as the following two paragraphs in the article give both a 0-based and 1-based approach, your point is moot.   Anything else?  73.254.89.77 (talk) 22:25, 18 February 2020 (UTC)
 * I agree that the previous phrasing was awkward. "There are two methods of demarcating calendar decades of Anno Domini years" reads much better. I also agree with Jc3s5h's point about the use of "Gregorian calendar": the current version implies that the two methods of demarcation are specific to the Gregorian calendar, and that calendars used before the Gregorian calendar was invented did not use these methods. O̲L̲D̲S̲T̲O̲N̲E̲  J̅A̅M̅E̅S̅  22:22, 18 February 2020 (UTC)
 * Did they? If users of other calendar systems used decade demarcation as is done in the English-speaking, Gregorian calendar-using, decimal number system-using world, we can certainly talk about them as well.  Of course, you'd have to cite such usage.....   73.254.89.77 (talk) 22:30, 18 February 2020 (UTC)
 * I'm agreeing with others here. I think Gregorian calendar is not appropriate. WildEric19 (talk) 15:48, 25 February 2020 (UTC)
 * Reasons? Is that demarcation not used with the Gregorian calendar? The sources clearly indicate it is. Is it used with other calendar systems?  Maybe, but none of your sources use anything but the Gregorian calendar.  So, to me it's perfectly simple:  Find a source that talks about decade demarcation in other calendar systems and they can be included, per WP:V.  Otherwise, we list what we've got sources for.   73.254.89.77 (talk) 15:28, 26 February 2020 (UTC)
 * 73.254.89.77|73.254.89.77 claims "but none of your sources use anything but the Gregorian calendar." But one of the sources in the article is from the British Library and contains "1st decade of the 16th century". This decade occurred before the Gregorian calendar was created. It is customary when writing about European history to use the Julian calendar for events between 45 BC and the adoption of the Gregorian calendar in the territory where whatever event being discussed occurred, so it is highly probable the British Library intended this as a Julian calendar date. Jc3s5h (talk) 17:54, 26 February 2020 (UTC)
 * So, on a circa spanning around 10 years, you are going to split hairs between a handful of days. Unbelievable. The source you selected is using that terminology because they don't know when the work was created. It is an educated guess with a 10-year margin of error. Does 10-year margin of error even matter if it is Julian or proleptic Gregorian?  At all? No. In the context of an approximation of 10 years does it matter if the decade commonly demarcated as 0-based or 1-based? Not at all. Besides, I already offered to compromise with "years of the Julian and Gregorian calendars" and you ignored that compromise.  Make up your mind. 73.254.89.77 (talk) 22:38, 27 February 2020 (UTC)

Back in February 2020 while this discussion was ongoing, User:Oldstone James made a self-described interim edit stating


 * There are two methods of demarcating Gregorian calendar decades:

Since the discussion seems to have consensus that "Gregorian calendar" has consensus, I have changed it to "anno Domini". Someone may think "Common Era" is more appropriate, but I think "anno Domini" is more widely understood. I am expecially concerned that people who understand "CE" won't understand "Common Era". Jc3s5h (talk) 16:11, 5 August 2020 (UTC)

Visual aid
This is about the comparison table last seen in revision 945780415.

@WildEric19: In response to "We came in agreement a long time ago that we don't need this table." (diff), I'm sorry but I've been unable to find a statement on this talk page about problems this visual aid would create. I'd appreciate if you could help me find this agreement, or rather the reasons behind it? I assume it is not the general concept of a visualisation that is in disputation, but rather a problem with the specific information I made available in this table?

The only thing I was able to find in relation to the table was someone saying its useful, and various arguments about the label "Nth decade of …". These labels were no longer present. And apart from the table and its label, I believe this was adequately addressed on 9 February 2020 ("millions of citations").

Thanks! --Krinkle (talk) 20:12, 23 April 2020 (UTC)
 * @Frond Dishlock, Blurryman, Jc3s5h: Apologies for the direct pings. It looks looks like WildEric and Oldstone James are both no longer active on the wiki (for unrelated reasons). I'd appreciate your perpectives on the above. I'd be happy to learn about something I may've missed. I don't want to step on any toes. Thank you, --Krinkle (talk) 01:44, 3 May 2020 (UTC)


 * @Krinkle Sorry for the delay in replying. I would support the insertion of the table in the form you last used, before it was undone by WildEric19. I have been following this article for some time, and I am not aware of any specific discussion or agreement about its inclusion, and I was rather surprised when your edit of 16 March 2020 was reversed by WildEric19 (who has now resigned from Wikipedia) because it was he who originally introduced such a table here. From memory, I believe it was later arbitrarily deleted and reinserted a few times, without any discussion, during the flurry of edits at the beginning of this year. --Blurryman (talk) 23:51, 15 May 2020 (UTC)
 * Any element that makes articles unusually wide make them more difficult to navigate. I don't think the table is worth the hassle the unusual width creates. Jc3s5h (talk) 00:14, 16 May 2020 (UTC)

"Decade (redirect)" listed at Redirects for discussion
A discussion is taking place to address the redirect Decade (redirect). The discussion will occur at Redirects for discussion/Log/2021 January 27 until a consensus is reached, and readers of this page are welcome to contribute to the discussion. 𝟙𝟤𝟯𝟺𝐪𝑤𝒆𝓇𝟷𝟮𝟥𝟜𝓺𝔴𝕖𝖗𝟰 (𝗍𝗮𝘭𝙠) 10:22, 27 January 2021 (UTC)

The "Usage methods compared" graph is messy.
The graph titled "Usage methods compared" seems to be very messy and confusing. Shouldn't it just look like the following? Peter J. Yost (talk) 14:41, 23 June 2021 (UTC)


 * Nevermind, I hadn't understood the graph correctly. Peter J. Yost (talk) 14:41, 23 June 2021 (UTC)


 * No, Peter. The 1-to-0 decade was correct, because I once believed that a decade could start for example, 2010, but it actually didn't start until 2011, a year later. So it made me realize how dumb-minded I felt. Now we can finally agree to disagree that a decade isn't until the number one like millenniums or centuries. You did pretty good. Darrion "Beans" Brown 🙂 (my talk page / my sandbox) 01:19, 21 October 2022 (UTC)

Removal of "ordinal"
The word "ordinal" was added in this edit. I have removed it because the word "ordinal" applies to things that are fundamentally ordered, while "cardinal" are used for counting things that have no inherent order. Thus, all dates are ordinal, no matter whether the count begins at 0 or 1, and no mater whether suffixes like -st, -rd, or -th are used. Hence it is inappropriate to use the word "ordinal" to differentiate between the two numbering systems. Jc3s5h (talk) 02:10, 24 July 2022 (UTC)

Enough with the decade beginning debates
I would like to oppose that like a century or a millennium (1901-2001), a decade doesn't begin without the number one, geographically. As we can see through the Gregorian calendars, the final result is clear that a decade is not ready without the one in it. For example, the 2020s decade didn't begin until January 1, 2021. I propose for any decade article on Wikipedia that mentions any decade starting at ***0 to be changed to prove that it always starts with ***1 starting with any first decade you can find. My prediction, my matter. There... CASE CLOSED!

Links to prove:    Darrion "Beans" Brown 🙂 (my talk page / my sandbox) 01:18, 21 October 2022 (UTC)
 * You don't get to close the case. If you try to enforce your belief by editing articles, it could lead to administrative action against you. Jc3s5h (talk) 13:08, 21 October 2022 (UTC)
 * Chronologically, a decade shall be counted as a period ending after a multiple of ten years, just as a century shall be counted as a period ending after a year which is a multiple of one hundred. However, it needn't be wrong to count the years 1900-1999 as a century, although I think those years should be referred to as a hundred-year-period rather than a century, as a century should be defined as a period starting with the year 1 AD and ending with the year 100 AD or otherwise as a period starting after a multiple of a hundred years and ending after the following 100-multiple years (i.e. starting with a year with the final digits 01 and ending with the following year with the final digits 00).
 * In some language like Swedish, the 20th century seems to be translated as nittonhundratalet (1900-talet), although it is not a correct translation. I think the correct translation of the 20th century should be det tjugonde seklet or det tjugonde århundradet (compare Norwegian det 20. århundre) and nittonhundratalet should be the translation of the 1900s. Many Swedish don't understand that there is a difference between the 1900s (1900-talet) and the 20th century (det tjugonde århundradet), as the 1900s is the years 1900-1999, in contrast to tjugonde århundradet (the 20th century) which starts with 1901 and ends with 2000. 212.100.101.104 (talk) 22:04, 19 August 2023 (UTC)

Decades in other languages
Is English the only language which recognizes a decade as a period which ends after a multiple of ten calendar years? For example, in Swedish a decade seems to be recognized as a period with the "joint ten-digit" (i.e. the years 1990-1999, the nineteen-nineties, in Swedish referred to as nitton-nittiotalet or nittonhundranittiotalet), despite the fact that a period with the "joint ten-digit" does not end after a multiple of ten years. Swedish people seem to not consider at all that a multiple of ten years are past at the end of a year ending on the digit 0, in contrast to English-speaking people who seem to consider this.

In English, a period ending after a multiple of ten years, i.e. the years 1971-1980, is normally referred to as the eighth decade of the 20th century, which in Swedish would be translated as det åttonde (8:e) decenniet av det tjugonde (20:e) seklet or det tjugonde (20:e) seklets åttonde decennium, but it seems that the Swedish language is so undeveloped that it so far hasn't become a "korrekt språkbruk" ("correct language use") to say "seklets Xth decennium", even though this should become a general norm to say a decade, just as in English.

Just as a century always ends after a multiple of a hundred years, a decade shall as well end after a multiple of ten years: As the 20th century ends in the end of 2000, the tenth decade of the 20th century shall be referred to the years 1991-2000 (not 1990-1999), the ninth decade of the 20th century the years 1981-1990 (not 1980-1989) and so on.

I wonder if it is possible to report a request to Svenska Akademiens ordlista (SAOL; the word list of the Swedish language) to define a decade as a period starting on a year ending on the digit 1 and ending (in the end) on the following year which is a multiple of 10. If SAOL receives such a request, it will eventually change the Swedish definition of a decade from a period of years with the shared ten-digit to a period which ends after a multiple of ten years. 212.100.101.104 (talk) 21:53, 19 August 2023 (UTC)


 * Please don't waste Svenska Akademien's time with your pet re-definition projects, BjörnBergman. - Tournesol (talk) 20:37, 28 August 2023 (UTC)
 * I think what "BjörnBergman" tries to say is important to consider. If English-speaking refer to for example the ten years 1981-1990 as the ninth decade of the 20th century, it should be referred to the same in other languages, for example Swedish. The Swedish translation of the ninth decade of the 20th century would be nionde (9:e) dececnniet av 20:e seklet or 20:e seklets nionde decennium.
 * Plus, the "ninth decade of the 20th century" is supposed to be referred to the years 1981 to 1990, rather than 1980-1989, as a decade is supposed to be defined as a period ending after a multiple of ten years. The first decade AD, which started with year 1 (as no year 0 exists), ended with year 10, as ten years were past in (the end of) year 10 and not year 9. The first decade of the 21st century is as well supposed to be defined as January 2001 - December 2010, and not 2000-2009. 217.21.226.230 (talk) 11:16, 30 August 2023 (UTC)
 * (I speak Swedish here as it would be easier to talk to a Swedish wikiuser) Tournesol, i vissa sammanhang säger man faktiskt det första decenniet av det X:e seklet, men det kanske inte du känner till. Om man exempelvis säger det första decenniet av 21:a seklet så menar man ju det årtionde som började år 2001 och upphörde år 2010, vilket icke är detsamma som det så kallade tjugo-nollnoll-talet, som är åren 2000 till 2009. 1940-talet (åren 1940-1949) är likaså inte heller detsamma som det femte decenniet av 20:e seklet (som är åren 1941-1950). 217.21.226.230 (talk) 08:16, 1 September 2023 (UTC)
 * I think you shall note something when searching for "femtonhundratal" on SAOB (Svenska Akademiens ordbok). According to SAOB, "femtonhundratalet" is referred to the years 1500 to 1599, which i det närmaste sammanfaller med "sextonde århundradet" (1501-1600); I think is an important reference which proves that i.e. 1900-talet in fact isn't synonymous with tjugonde århundradet (the 20th century), as tjugonde århundradet isn't the years 1900-1999, but 1901-2000, just as nittonde århundradet is 1801-1900 and not 1800-1899. The English phrase "19th century" should in Swedish be translated to nittonde (19:e) århundradet and not 1800-talet. 212.100.101.104 (talk) 11:09, 3 September 2023 (UTC)