# One Third **URL:** \ **Category:** Factual Questions\ **Created:** [February 3, 2006, 7:41pm UTC](https://boards.straightdope.com/t/one-third/342885 "2006-02-03T19:41:48Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Paradise\_Pete](https://avatars.discourse-cdn.com/v4/letter/p/ee59a6/32.png) [@Paradise\_Pete](https://boards.straightdope.com/u/Paradise_Pete)\ **Post date:** [February 3, 2006, 7:41pm UTC](https://boards.straightdope.com/t/one-third/342885/1 "2006-02-03T19:41:48Z")
We have the prefixes semi and hemi for things that are one-half of the whole, as in semi-annual and hemisphere. Is there a prefix for one-third? Thanks in advance, - Thirdless in Theattle P.S. I notice they can smoothly handle this in Malaysian. [http://www.seasite.niu.edu/indonesian/TataBahasa/prefix/Prefix\_se-/](http://www.seasite.niu.edu/indonesian/TataBahasa/prefix/Prefix_se-/) ---
**Author:** ![Birdmonster](https://avatars.discourse-cdn.com/v4/letter/b/71e660/32.png) [@Birdmonster](https://boards.straightdope.com/u/Birdmonster)\ **Post date:** [February 3, 2006, 8:10pm UTC](https://boards.straightdope.com/t/one-third/342885/2 "2006-02-03T20:10:09Z")
Wow. That’s a fantastic question. I’m going to give it a bump. I keep thinking tertiary, but that means third in a list as oppossed to one third. And my google-fu is failing. I think we may need to fabricate one. ---
**Author:** ![Mindfield](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mindfield/32/19759_2.png) [@Mindfield](https://boards.straightdope.com/u/Mindfield)\ **Post date:** [February 3, 2006, 8:50pm UTC](https://boards.straightdope.com/t/one-third/342885/3 "2006-02-03T20:50:37Z")
AFAIK there is only _demi_ as reference to half of something (_demi-tasse_, _demi-god_, etc.) _Semi_ on the other hand referw simply to a non-specific _part_ of the whole. In all other reference one would just use _quarter_, _half_, _three-quarters_, etc. ---
**Author:** ![Kimstu](https://avatars.discourse-cdn.com/v4/letter/k/ecd19e/32.png) [@Kimstu](https://boards.straightdope.com/u/Kimstu)\ **Post date:** [February 3, 2006, 8:55pm UTC](https://boards.straightdope.com/t/one-third/342885/4 "2006-02-03T20:55:48Z")
> [@Mindfield](#): > > Semi on the other hand referw simply to a non-specific part of the whole. Nope, it means “half”. A semicircle is a half-circle, a semiquaver (musical note) is a half-quaver, semiannual means every half-year, and so on. You’re right that it’s also been adopted to mean an unspecified part, as in “semi-serious”, but the original meaning is specifically “half”. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 3, 2006, 9:02pm UTC](https://boards.straightdope.com/t/one-third/342885/5 "2006-02-03T21:02:48Z")
A semicircle is a half of a circle, and a hemisphere is a half of a sphere. And a hemidemisemiquaver is a half of a half of half of a quaver. So all three terms are in use meaning “half”. ---
**Author:** ![Kimstu](https://avatars.discourse-cdn.com/v4/letter/k/ecd19e/32.png) [@Kimstu](https://boards.straightdope.com/u/Kimstu)\ **Post date:** [February 3, 2006, 9:06pm UTC](https://boards.straightdope.com/t/one-third/342885/6 "2006-02-03T21:06:11Z")
By the way, “semi-” is from Latin _semis_, “one-half”. So since the Latin term for “one-third” is _triens_, I suppose you could use “triens-” or a derived form as the prefix you’re looking for. Triens-circle. Triens-annually. Eh, it doesn’t really sing, does it? Latin for “two-thirds”, by the way, is _bes_. Have fun! ---
**Author:** ![Spidey](https://avatars.discourse-cdn.com/v4/letter/s/ac91a4/32.png) [@Spidey](https://boards.straightdope.com/u/Spidey)\ **Post date:** [February 3, 2006, 10:06pm UTC](https://boards.straightdope.com/t/one-third/342885/7 "2006-02-03T22:06:23Z")
A pointless fact that I must share: To decimate something seems to mean to cut it into 10. Thus decimating an army would leave only 1/10 the amount of soldiers. ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [February 3, 2006, 10:09pm UTC](https://boards.straightdope.com/t/one-third/342885/8 "2006-02-03T22:09:55Z")
> [@Spidey](#): > > A pointless fact that I must share: > > To decimate something seems to mean to cut it into 10. Thus decimating an army would leave only 1/10 the amount of soldiers. I think that this is incorrect. traditionally to decimate was to remove 1 in 10 leaving you with 9/10ths the ammount of soldiers. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [February 3, 2006, 10:10pm UTC](https://boards.straightdope.com/t/one-third/342885/9 "2006-02-03T22:10:55Z")
> [@Spidey](#): > > A pointless fact that I must share: > > To decimate something seems to mean to cut it into 10. Thus decimating an army would leave only 1/10 the amount of soldiers. That’s actually not what the word meant, and since pesky ntpickers have bugged _me_ about it, I’m passing on the ritual. “Decimation” was a formal group punishment in which a randomly-selected tenth of the soldiers were executed. It was meant to boost morale, apparantly. In modern times, I (and just about everybody else) use the word to mean “clobber to a fraction, possibly one-tenth, of its former self”. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [February 3, 2006, 10:11pm UTC](https://boards.straightdope.com/t/one-third/342885/10 "2006-02-03T22:11:58Z")
Damn you, gazpacho. Revenge will _also_ be served cold! ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [February 3, 2006, 11:14pm UTC](https://boards.straightdope.com/t/one-third/342885/11 "2006-02-03T23:14:51Z")
> [@Paradise Pete](#): > > IWe have the prefixes semi and hemi for things that are one-half of the whole, as in semi-annual and hemisphere. Is there a prefix for one-third? Possibly there is some technical one, but not one in common use. For good reason – we don’t commonly divide things into thirds. It’s much harder to do so accurately than halves. How would you produce a 1/3 circle, or 1/3 sphere? It’s not easy. We have hemi-, demi-, semi- because it’s common to divide things in half. Words & prefixes exist because people use them. If something doesn’t occur frequently in speech, it tends not to have a single word describing it, instead we have to use several words for it. ---
**Author:** ![Zeldar](https://avatars.discourse-cdn.com/v4/letter/z/b77776/32.png) [@Zeldar](https://boards.straightdope.com/u/Zeldar)\ **Post date:** [February 3, 2006, 11:26pm UTC](https://boards.straightdope.com/t/one-third/342885/12 "2006-02-03T23:26:01Z")
Maybe if things had continued to develop around the base 12 system, thirds would be a little more common. But our preferences for Base 2 and Base 10 counting puts thirds outside the system of clean cuts. Pi just adds to the confusion surrounding thirds. ---
**Author:** ![Ringo](https://avatars.discourse-cdn.com/v4/letter/r/779978/32.png) [@Ringo](https://boards.straightdope.com/u/Ringo)\ **Post date:** [February 4, 2006, 1:42am UTC](https://boards.straightdope.com/t/one-third/342885/13 "2006-02-04T01:42:02Z")
All that quickly comes to mind is that pregnancies are often subdivided into _tri_mesters. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [February 4, 2006, 3:23am UTC](https://boards.straightdope.com/t/one-third/342885/14 "2006-02-04T03:23:59Z")
> [@Ringo](#): > > All that quickly comes to mind is that pregnancies are often subdivided into _tri_mesters. That’s true enough, but I have read that semester has nothing to do with semi, but six and therefore means 6 months (although in the US they are 15 weeks). So trimester ought to mean three months, which as it happens is also 1/3 of six months. I am a little surprised no one has mentioned sesqui-, one and a half. For example a sesquipedalian word is one that is a foot and a half long. ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [February 4, 2006, 2:40pm UTC](https://boards.straightdope.com/t/one-third/342885/15 "2006-02-04T14:40:44Z")
And to cut into thirds you _trisect_ it. (but not waht the Op is looking for) Brian ---
**Author:** ![scotandrsn](https://avatars.discourse-cdn.com/v4/letter/s/a4c791/32.png) [@scotandrsn](https://boards.straightdope.com/u/scotandrsn)\ **Post date:** [February 4, 2006, 2:55pm UTC](https://boards.straightdope.com/t/one-third/342885/16 "2006-02-04T14:55:26Z")
> [@Hari Seldon](#): > > So trimester ought to mean **three months** , which as it happens is also **1/3 of six months**. I know who got a “D” in fractions! 😃 In re the OP, I recall some aiuthor in a discussion about something pointing out that a great number of languages focus on dividing in half, whereas further subdivisions do not receive the same attention. The specific point made was that in many languages, as in English, the words for “two” and “half” bear no semantic relation to one another. By the time you get to greater subdivisions, the words are similar: thee and third, four and fourth, etc. Perhaps the lack of the OP’s suffix is a related phenomenon. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [February 4, 2006, 9:03pm UTC](https://boards.straightdope.com/t/one-third/342885/17 "2006-02-04T21:03:06Z")
> [@scotandrsn](#): > > I know who got a “D” in fractions! 😃 Oops! I think a gremlin got into the keyboard. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [February 4, 2006, 9:07pm UTC](https://boards.straightdope.com/t/one-third/342885/18 "2006-02-04T21:07:42Z")
> [@Paradise Pete](#): > > We have the prefixes semi and hemi for things that are one-half of the whole, as in semi-annual and hemisphere. Is there a prefix for one-third? WAG Half-Hexic? ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [February 4, 2006, 9:19pm UTC](https://boards.straightdope.com/t/one-third/342885/19 "2006-02-04T21:19:55Z")
> [@spingears](#): > > WAG Half-Hexic? If we’re talking fractional values, half-hexic would be twelvic (dodecadric?) Double-hexic (i.e. two times one-sixth) would be a third. ---
**Author:** ![TJdude825](https://avatars.discourse-cdn.com/v4/letter/t/dec6dc/32.png) [@TJdude825](https://boards.straightdope.com/u/TJdude825)\ **Post date:** [February 5, 2006, 7:02am UTC](https://boards.straightdope.com/t/one-third/342885/20 "2006-02-05T07:02:20Z")
> [@Hari Seldon](#): > > I am a little surprised no one has mentioned sesqui-, one and a half. For example a sesquipedalian word is one that is a foot and a half long. Okay. What Latin prefix would imply “the fraction X such that when you multiply X by one-and-a-half, you get a half”? :dubious: \ Could we use “sesqui-” to eliminate the use of the word “dotted” in discussing music notes? For example, a dotted quarter note is one and a half eighth notes. Using the british names,\* a dotted whole note would be a sesquiminim, a dotted half note would be a sesquicrotchet, and a dotted quarter note would be a sesquiquaver or sesquaver, all of which might make decent band names. \*whole note = semibreve half note = minim quarter note = crotchet eighth note = quaver \ [Next page](https://boards.straightdope.com/t/one-third/342885.md?page=2)