Explain xkcd: It's 'cause you're dumb.
A "sesquiannual" meeting is one that occurs one and a half times every year; equivalently, 3 times every 2 years, or once every 8 months (this could be taken even more literally by having one meeting during each year, and another meeting which spans midnight every other New Year's Eve, thus having a one and a half meetings each year).
The term comes from the Latin prefix "sesqui-", which means "one and a half", and the root word "annual", which equates to "…times per one year". The root word "annual" is commonly confused with the suffix "ennial", meaning "one time per x years." In particular, “sesquiannual” should not be confused with “sesquiennial”, meaning "one time per one and a half years" or every one and a half years (18 months). Note that the Wiktionary entry on sesquiannual has both meanings listed – both 8 month and 18 months intervals. This is an extension of the common confusion between "biannual," meaning "twice a year", and "biennial", meaning "once every two years". Compare with the Sesquicentennial Exposition celebrating the first 1½ centuries of the United States, and "sesquibicentennial", being 'half and two' hundred years, i.e. 250.
The joke suggests that only a competent linguist could understand the word “sesquiannual”. One reason for this is that the prefix “sesqui-” is rare, so those who know its meaning are likely to be linguists. Another is that a competent linguist should be able to distinguish between “sesquiannual” and “sesquiennial”.
If you understand this then you can join the Linguistics Club. While most organizations attempt to ensure that the schedule of their meetings are clear to participants so that everyone will attend, the club in the comic deliberately instills an ambiguity for those outside their target demographic. Their membership will thus swell with the desired cognoscenti who remain unconfused, and maybe also a few lucky guessers.
Once the applicant correctly understands the frequency of meetings, presumably they are told at least one meeting date in the cycle so that an attendance can be made.
Regarding the title text, a tautology is a statement that is true (or self-evident) because of its logical form, such as "all birds are birds" or "A = A." As such, the statement "the Tautology Club meets on the date of the Tautology Club's meeting" is itself tautological.
While the membership requirement for the Linguistics Club is merely to know the intended frequency, the Tautology Club's stipulation appears to require an eligible member to derive a valid meeting date from thin air without any clue at all (and no indication that there is even a regular cycle of any kind). This would definitely be more of a challenge.
The title text has a connection to 703: Honor Societies in which Cueball creates a Tautology Club where tautologies are used in practically every spoken sentence.
- [Megan talks to Ponytail.]
- Megan: You should come to our Linguistics Club's sesquiannual meeting.
- Megan: Membership is open to anyone who can figure out how often we meet.
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If biannual is ambiguous, meaning either biennial (every two years) or semiannual (twice each year), then isn't sesquiannual similarly ambiguous, meaning either every 1.5 years (every 18 months), or 1.5 times a year (every 8 months)?
Pete (talk) 06:38, 11 November 2015 (UTC)
- If I'm confused I think of plants: Annuals, biennials and perennials - this last one being the important one as I *know* there is no such thing "perannual", so the ending I want must be "-ennial". 126.96.36.199 08:58, 11 November 2015 (UTC)
Could it not mean it meets one and a half tines each year, so once during each year then every other new years it meets with half the meeting before the ball drop and the other half after? 188.8.131.52 06:41, 11 November 2015 (UTC)
You know, I always thought the roots of "sesqui-" equated to "six quarters" (i.e. 1½). Today I learn that it's apparently "a half and (the original unit, about to be mentioned)". I'm glad I read this place. 184.108.40.206 06:49, 11 November 2015 (UTC)
- ...and then I nearly made a total mess of the editing, while trying to add info and 'correct' it, but I think it's back to how it should be, with the correct amount of appropriate justifications. (Note, "sesquicentennial" could be read as "one half (0.5) plus one hundred (100) years", i.e. 100.5 years, but the intended grammatical formation is "one-half-plus-one (1.5) hundred years", i.e. 150 years. Whilst "sesquicentannual" would doubtless be... give or take, according to rigor... something that occured every two days, ten hours and twenty-four minutes, I suppose.) 220.127.116.11 07:32, 11 November 2015 (UTC)
- I thought that the root of the Russian word "poltora" (same meaning) was "half of three", but it's actually "half to two". Now if I could only understand why the English phrase "half again as much" also means 1.5 times...
- On-topic, I understand "biannual" as "every 6 months", so by extension "sesquiannual" would mean "every 8 months". Not to be confused with "sesquiennial", which does mean "every 18 months" (as in Fifth Sesquiennial Best Article Elections of Russian Uncyclopedia; sadly the Sixth Elections had not proceeded on the account of only having one eligible candidate, and there are still no eligible candidates for the Seventh, due in July). --18.104.22.168 07:52, 11 November 2015 (UTC)
- Well, 'round these parts it's generally said in a different order, as "half as much again", which is more obviously 50% on top, or 150%.
- If only I could stop people saying "four times less". One can only presume they mean 25%, a quarter (the reverse of the quarter being made "more by four times" to make the whole). But three times less would be a third, two times less a half and one times less... well, that breaks things. Rather than the unaltered 100%, parsing that suggests either 0%, or possibly half, if the reverse is "one time more (on top of the starting point)". In which case "four times less" is 20%, so that "four times more" adds four more 20%s to get you up to the 100%...
- Which is a totally different mathematical conundrum from removing 10% then adding 10% to get to 99%. (original - (10%*original) = 90%*original = midstep. midstep + (10%*midstep) = 90%*original + (9%*original) = 99% original.) Or adding 10% (110% original) then removing 10% (-11% original), which is commutatively the same pair of operations (*1.1, *0.9) in reverse.
- But that's probably not relevent. 22.214.171.124 08:33, 11 November 2015 (UTC)
'biweekly' means both once every two weeks and twice a week. The explanation implies it only means once every two weeks. --126.96.36.199 13:46, 11 November 2015 (UTC)
- The only thing in common there is the prefix. "bi-" means 2 and "sesqui-" means 1.5, no matter what. In the case of "biweekly", that can mean "two per week" or "every two weeks," and that's because "weekly" can take either meaning. The same applies to "monthly" for "bimonthly."
- Annual, however, is different. "Biannual" only means "two per year." That's it. It doesn't mean "every two years," because that's a different word: 'biennial'. In other words, the "annual" root means "once a year", and the "-ennial" suffix means "once every X years".
- The reason for this is that "annual" and "-ennial" were derived from Latin words that already had the distinction, while "weekly" and "monthly" were created from English words, with no way to distinguish the two meanings.
- Confusing? Blame the Romans. 188.8.131.52 23:38, 11 November 2015 (UTC)
- I agree with you; however, Merriam-Webster does not. The dictionary definition for "biannual" lists both "twice a year" and "every two years", listing "biennial" as a synonym. This is the problem with descriptive languages: if enough idiots use a word wrong, it becomes right.184.108.40.206 00:14, 12 November 2015 (UTC)
- Tell those aforementioned idiots that we're going to decimate them, for their crimes against language... We won't actually have to work as hard as they think we will, but they'll be living in fear of a disproportionate degree of vengeance, at least until they get the message. ;) 220.127.116.11 00:33, 14 November 2015 (UTC)
"Regarding the title text, a tautology is a statement that is true because of its logical form, such as "all birds are birds" or "A = A." Maybe tautology in grammatical context is more appropriate here, since the comic is linguistics-themed: "In grammar, a tautology (from Greek tauto, "the same" and logos, "word/idea") is an unnecessary repetition of meaning, using more than one word effectively to say the same thing (...)" or "saying the same thing twice", as in the title text: (...) Tautology Club, which meets on the date of the Tautology Club meeting.
18.104.22.168 14:06, 11 November 2015 (UTC)
Just to add a real-world example for additional confusion on the issue: The Society for the Anthropology of Lowland South America has a sesquiannual conference which is held every 18 months. The last conference was on June 26, 2014 and the next one is January 7, 2016.
22.214.171.124 15:45, 11 November 2015 (UTC)
The current second paragraph says:
On the other hand [and the crux of the comic in general], 'sesqui' can be interpreted as a prefix meaning '1.5'. For example, the US sesquicentennial was celebrated on July 4, 1926 (after 150 years), so the confusion comes from people who think the meetings would be every 8 months (as above) or every 18 months (here). The confusion is related to the distinction between 'biweekly' (once every two weeks) and 'semiweekly' (once every half-week, i.e., twice a week), and bimonthly (twice a month or every two months). 'Biannual' and 'biennial' only furthers this confusion (as in this case, 'biannual' and 'semiannual' are synonymous when the prefixes usually are not).
...which misses the point. Sesqui is 1.5, bi is 2 (c.f. bicycle, 2 wheels), semi is 0.5 (c.f. semicircle, half a circle). The issue is with the -ennial (X years per event) and -annual (X events per year). Semiannual (half an event per year, thus one event every two years) is cognate with biennial (two years between events). Biannual only means 'two per year', unless misused. Semiennual would match that (half a year per event), but I'm not sure that's ever used, like perannual (1 event a year), in the face of the identically descriptive perennial (a year between all successive events). ...I think. Tablet on-screen keyboard obscures most of what I'm typing, so there'll be no proofreading of this point to make sure I've not boobed. It'll have to stand. 126.96.36.199 16:33, 11 November 2015 (UTC)
- Second paragraph was already changed (for the better?) by the time I came here, before I saw this comment. I expanded and refined what remained, so much so as to go and make it into three (or was it four?) mostly shorter paragraphs. Hope everyone approves. If not, edit or revert! 188.8.131.52 12:47, 12 November 2015 (UTC)
I'm just going to leave this Google Trends link here... Celloman (talk) 16:45, 11 November 2015 (UTC)
As another note, a group that meets every 8 months and a group that meets every 18 months will only overlap every 6 years. But my sesquibiennual group has the room booked, so they'll both have to reschedule 184.108.40.206 23:48, 11 November 2015 (UTC)
Maybe I am overthinking it, but 1.5 times a year shouldn't be every 8 months, shouldn't it be every9? After all it's is every 1 time period(6 months) and half of that(3), which the sum is 9. Unless it is supposed to be 8 because it is 8/12=2/3 being 3/2(1.5) flipped?
-220.127.116.11 00:37, 12 November 2015 (UTC)
- Sounds like you have perhaps gone a step further than you should have. One every 9 would be 1.333··· per year, or four every three years if simplified. Not sure where the 6 months for 1 time period idea comes from. The 'flip', i.e. the inverse, of the 1.5 is the point. (See the semi-/bi- thing someone mentioned above. Each of them the inverse of the other, thanks to the annual/ennial distinction of which way up the any fraction applies.) 18.104.22.168 11:30, 12 November 2015 (UTC)
- I think it is the 3/2 that makes him think of half of 12 = 6 months. But it is not 3/2 but 2/3 of a year, which comes in at 8 months. And 8*3 = 24 month = two years, so three meetings in two years or 1.5 meeting each year. But I guess the long discussion above proves the point that they will only get half the intended audience. No one who is not interested would bother, and still they will loose half of those that are, since the word is defined as meaning both in the dictionary, although it probably oiriginaly only was supposed to mean once every 8 month... :) --Kynde (talk) 14:16, 12 November 2015 (UTC)
I wonder if the comic’s use of “sesquiannual” was also meant to be a reference to the word “sesquipedalian” (many-syllabled). My school’s literary club nicknamed themselves something like the “sesquipedalian word lovers’ club”, so that’s the word I immediately thought of when I read the comic. In fact, I didn’t know until now there were other words beginning with “sesqui-”. – RoryOKane (talk) 14:15, 12 November 2015 (UTC)
- "Sesquipedalian" literally means "[having the quality of] a foot and a half," although I'm not sure if it's referring to the length unit of the Imperial system or the metric unit of poetry. If the later case, that would mean that for English a sesquipedalian word must have exactly three syllables, since the natural meter of English is iambic pentameter and the iamb is two syllables long. 22.214.171.124 21:24, 13 November 2015 (UTC)NXTangl
In case someone's interested, French has similar distinctions/confusions. Twice a year = biannuel, once every two years = biennal. With another option for the latter: bisannuel (same root as biannuel but the extra S changes the meaning). There are also two roots for 'month': twice a month = bimensuel, once every two months = bimestriel, although bimensuel is sometimes misused or misunderstood.
Zetfr 15:22, 12 November 2015 (UTC)
'Sesqui' means "one and a half" and 'annual' means "yearly". But if the meeting is held (on average) every eight months, then there will be TWO meetings every second year — which flies in the face of the definition of 'sesquiannual'. So you must hold 1 meeting and half of another meeting in a given calendar year.... and the only way to do that is, at the second meeting, go through approximately half of the order of business and then call to adjourn. Reconvene the following year and complete the meeting from the point of adjournment. - RAGBRAIvet (talk) 16:45, 12 November 2015 (UTC)
- Untrue. You could also hold one meeting during the summer, then every other year hold four-hour meeting beginning at 10:00PM new year's eve. 126.96.36.199 21:24, 13 November 2015 (UTC)NXTangl.
Not sure if anyone noticed... But I think we all just got nerd sniped. Bon (talk) 06:45, 13 November 2015 (UTC)
Just undone a change that re-ascribed 'sesquibicentennial' to meaning 300 years, probably under the impression that it's "1.5 x 200 years", rather than "(0.5+2) hundred years" or 250 of them. (Seriously, "sesqui-" is functionally "a half and..." so is only "1.5x" when added to a unity-based prefix that makes it "a-half-and-one times <foo>". Also, 300 years is already termed a tricentennial and needs no more complicated construction.) One example of it being used: http://www.sacomaine.org/saco250.shtml - but there's probably something more definitive. 188.8.131.52 07:35, 13 November 2015 (UTC)
"A common method of having meetings "on the first and third Monday of every month" is strictly twice-monthly but also mostly, and ironically, once every two weeks..." Can't see the irony. Is my brain derping or or am I now that person? --Kaay (talk) 09:44, 13 November 2015 (UTC)
- The irony is that the possibly misused Bimonthly (Semimonthly, twice a month) is almost the same as Biweekly (in the sense of every two weeks). And indistinguishable, most of the time, from each othet, going just by two adjacent events... Or so it appears to me... 184.108.40.206 22:33, 13 November 2015 (UTC)
Could it be possible that the idea of the usage of the word "sesqui-" came from "Sesquilinear form", a generalizaton of biliear form, used for example to define the innner product in hilbert spaces? https://en.wikipedia.org/wiki/Sesquilinear_form for more info. I think that this could be a possibility, based on the author background. 220.127.116.11 (talk) (please sign your comments with ~~~~)