# seven day weeks and names of days **URL:** \ **Category:** Factual Questions\ **Created:** [June 25, 2001, 3:09am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034 "2001-06-25T03:09:02Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [June 25, 2001, 3:09am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/1 "2001-06-25T03:09:02Z")
So in Japanese, the first two days of the week are called Nichiyobi and Getsuyobi. Literally translated, these names mean “Sun Day” and “Moon Day.” I just figured they got that from the west - though interestingly the rest of the names of their days have nothing to do with ours. For the curious, the names of the other days are “fire,” “water,” “wood,” “gold,” and “earth.” But then I started wondering - where does the seven day week come from? At first I thought we just got it from judaism through christianity, but don’t I recall that the Romans also had a seven day week? And if the seven days had come through christianity from judaism, why would they have such “pagan names” derived from natural and non-christian mythological sources? And _did_ the Japanese adopt our seven-day week, or did they get it from somewhere else untraceable to the west? If so, then is it just a coincidence that they call their first two days by the “same” name as we call ours? There isn’t, by any chance, a correspondence between the elements named in their other days and the gods our days are named after, is there? -Kris ---
**Author:** ![bizerta](https://avatars.discourse-cdn.com/v4/letter/b/3be4f8/32.png) [@bizerta](https://boards.straightdope.com/u/bizerta)\ **Post date:** [June 25, 2001, 3:26am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/2 "2001-06-25T03:26:02Z")
Sunday, Moonday, Mars day (Mardi), Mercury (Mercredi), Thor’s day (Jeudi, Jupiter), Vendredi (Venus day), Saturn day. It appears that they are named for all the celestial bodies that are visible to the naked eye AND move amongst the stars. ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [June 25, 2001, 3:35am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/3 "2001-06-25T03:35:18Z")
Sorry, my post is kind of “english-centric” so I forgot to take into account the names of the days in the Romance languages. In English, the days are named after The Sun The Moon Thiw (sp?) Odin Thor Frigg Saturn So the first two are natural entities, the next four are norse gods, and the last is either a roman god or one of the planets. My question is, is this seven day week descended from the roman system, or the jewish system?@In either case, why are natural and norse names used instead of roman names or christian names or jewish names? And also in either case, are the two systems (jewish and roman) related or were their seven day weeks arrived at independantly? And lastly, where did Japan and other cultures get their seven day week? And are their day-names in any way related to the “western” day-name traditions? -Kris ---
**Author:** ![Cap\_n\_Crude](https://avatars.discourse-cdn.com/v4/letter/c/b9e5f3/32.png) [@Cap\_n\_Crude](https://boards.straightdope.com/u/Cap_n_Crude)\ **Post date:** [June 25, 2001, 3:38am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/4 "2001-06-25T03:38:57Z")
My understanding is that most English names of the days of the week are from the Germanic tongues. They’re the names of gods from the Norse myth cycle. Specifically Tuesday (for Tiw, or Tyr); Wednesday (for Woden or Odin); Thursday (for Thor); and Friday (for Frey). ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [June 25, 2001, 4:11am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/5 "2001-06-25T04:11:13Z")
Yes, that is what I said… 😉 My question was not “where do the names come from” but rather, why those names and not roman or jewish names? And why seven days? And is there any relationship between our day-names and those of other seven-day-week cultures, for example, the Japanese, who do share “sun” day and “moon” day with us but who seem to have completely different names for the rest of the days. Are these questions clear to everyone or should I just start over and try again? 😉 -Kris ---
**Author:** ![Johanna](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johanna/32/8318_2.png) [@Johanna](https://boards.straightdope.com/u/Johanna)\ **Post date:** [June 25, 2001, 4:20am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/6 "2001-06-25T04:20:56Z")
They are all planets. Since planets were mythologized, they are also names of deities. As for Japanese _Nichiyobi_ and _Getsuyobi_: these are translations of Sanskrit _ravivâra_ (‘Sun-day’) and _somavâra_ (‘Moon-day’), respectively. This Indian & Sanskrit influence came to Japan via Buddhism. The remaining five days are the Chinese five elements, important to Confucian and Taoist cosmology, and used in countries influenced by Confucianism, like Japan. In Sanskrit, all seven days of the week follow the same planetary pattern, in the same order, as in European languages. You know, we already had a thread on days of the week in various languages, you should refer to that (a lot of information in there which I’m not going to reproduce here): [http://boards.straightdope.com/sdmb/showthread.php?threadid=65344](http://boards.straightdope.com/sdmb/showthread.php?threadid=65344) As to why ancient cultures from India to Germany had seven days in the week and named them after planets, that goes back to ancient Babylonian astrologers, the first people in the world to make a systematic study of planetary motions and build a calendar therefrom. The Hindus in India as well as the ancient Romans picked up the days of the week and the Zodiac signs from the Chaldean astrologers. ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [June 25, 2001, 4:47am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/7 "2001-06-25T04:47:56Z")
I couldn’t find the thread wherein we explained how the ordering occurred–if you take the seven heavenly bodies (sun, moon, and five planets) and order them according to how long it takes them to progress against the “fixed” star background, it would be Saturn, Jupiter, Mars, Sun, Venus, Mercury, and Moon. Dang. Not the same as the days of the week. O well. Now, assign each planet to an hour of the day, repeating the seven names over and over. The first hour of the first day will be Saturn’s. The first hour of the second day will be the Sun’s. And so on. That’s how the names of the planets were assigned to the days of the week. Our English names are Norse gods corresponding to the Roman gods. ---
**Author:** ![even\_sven](https://avatars.discourse-cdn.com/v4/letter/e/dfb087/32.png) [@even\_sven](https://boards.straightdope.com/u/even_sven)\ **Post date:** [June 25, 2001, 5:54am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/8 "2001-06-25T05:54:51Z")
I am sure that the seven days are related to lunar cycles. Seven is the handiest number that divides into 28. ---
**Author:** ![Protesilaus](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Protesilaus](https://boards.straightdope.com/u/Protesilaus)\ **Post date:** [June 25, 2001, 6:38am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/9 "2001-06-25T06:38:55Z")
The Babylonians seem to have been the first to name days of the week after planets/gods around 700 BC. The Romans replaced the names with their own gods when Constantine borrowed the idea of a week in AD 321. The idea of a week didn’t make it to Britain until the time of the Anglo-Saxon conquests, who took up some old Roman customs but kept their own religion and gods, hence the changes to the Norse gods in the English day names. ```auto Planet Ancient Planet-gods Day Name Babylonian Roman Anglo-Saxon (English) Sun Shamash Sol Sun Sunday Moon Sin Luna Moon Monday Mars Nergal Mars Tiw Tuesday Mercury Nabu Mercurius Woden Wednesday Jupiter Marduk Jupiter Thor Thursday Venus Ishtar Venus Freya Friday Saturn Ninurta Saturnus Saturn Saturday ``` Source of Chart: _Calendar: Humanity’s Epic Struggle to Determine a True and Accurate Year_, by David Ewing Duncan (p. 56) ---
**Author:** ![Floater](https://avatars.discourse-cdn.com/v4/letter/f/dc4da7/32.png) [@Floater](https://boards.straightdope.com/u/Floater)\ **Post date:** [June 25, 2001, 10:41am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/10 "2001-06-25T10:41:06Z")
> [@](#): > > \*Originally posted by Protesilaus \* > \*\* > Venus Ishtar Venus Freya Friday > \*\* Make that **Frigga** or **Frigg** instead. Ferya is another goddess. ---
**Author:** ![grimpixie](https://avatars.discourse-cdn.com/v4/letter/g/ecb155/32.png) [@grimpixie](https://boards.straightdope.com/u/grimpixie)\ **Post date:** [June 25, 2001, 11:10am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/11 "2001-06-25T11:10:26Z")
> [@](#): > > \*Originally posted by even sven \* > \*\*I am sure that the seven days are related to lunar cycles. Seven is the handiest number that divides into 28. \*\* I agree - for the same reason we have 24 hours in a day, 60 minute/seconds in an hour/minute and 360 degrees in a circle. All make doing mathematics in your head much easier… Gp ---
**Author:** ![bizerta](https://avatars.discourse-cdn.com/v4/letter/b/3be4f8/32.png) [@bizerta](https://boards.straightdope.com/u/bizerta)\ **Post date:** [June 25, 2001, 11:46am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/12 "2001-06-25T11:46:44Z")
> [@](#): > > I am sure that the seven days are related to lunar cycles. Seven is the handiest number that divides into 28. So where does 28 come in? A lunar cycle is 29.53 days. ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [June 25, 2001, 11:50am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/13 "2001-06-25T11:50:42Z")
> [@](#): > > \*Originally posted by grimpixie \* > \*\* > > > [@](#): > > > > \*Originally posted by even sven \* > > \*\*I am sure that the seven days are related to lunar cycles. Seven is the handiest number that divides into 28. \*\* > > I agree - for the same reason we have 24 hours in a day, 60 minute/seconds in an hour/minute and 360 degrees in a circle. \*\* I disagree. Definitely planets. and sun and moon ---
**Author:** ![Johanna](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johanna/32/8318_2.png) [@Johanna](https://boards.straightdope.com/u/Johanna)\ **Post date:** [June 25, 2001, 11:53am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/14 "2001-06-25T11:53:22Z")
A lunar cycle with respect to the sun is 29.53 days, but the moon goes through the Zodiac in about 28 days. In the time it takes the moon to get 360 degrees around the Zodiac, the sun has also gone about 30 degrees; the extra day and a half until the moon reaches conjunction with the sun is the difference. ---
**Author:** ![MrO](https://avatars.discourse-cdn.com/v4/letter/m/50afbb/32.png) [@MrO](https://boards.straightdope.com/u/MrO)\ **Post date:** [June 25, 2001, 11:53am UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/15 "2001-06-25T11:53:56Z")
> [@](#): > > \*Originally posted by Kris Rhodes \* > \*\*And lastly, where did Japan and other cultures get their seven day week? And are their day-names in any way related to the “western” day-name traditions? > > -Kris > \*\* I left Japan 8 years ago, and I’ve forgotten most of the language that I knew. But here in Korea they use the same Chinese characters to represent the days. Sunday = sun Monday = moon Tuesday = fire Wednesday = water Thursday = wood (or tree) Friday = gold (or metal) Saturday = dirt I don’t know how to post Chinese characters. I have enough trouble with smilies. ---
**Author:** ![Annie-Xmas](https://avatars.discourse-cdn.com/v4/letter/a/ecc23a/32.png) [@Annie-Xmas](https://boards.straightdope.com/u/Annie-Xmas)\ **Post date:** [June 25, 2001, 1:02pm UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/16 "2001-06-25T13:02:38Z")
The 28 days is related to the menstrual cycle. The first calenders were probably menstrual calendars. When men took things over, they switched it to the moon’s cycle (and made the number 13 unlucky, since 28 x 13 is 364). ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [June 25, 2001, 1:06pm UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/17 "2001-06-25T13:06:32Z")
I agree about the 28 day part. There aren’t too many factors that go into 28. Seven is one of them, and that works out very conveniently, because it lets you have four very identifiable quarters – Full Moon, Half Moon (first Quarter), New Moon, other Half Moon (last Quarter). Dividing further isn’t so easy to do in any case, and when you consider that the time perios would include fractional days it’s clear why they didn’t do it. Please note that 14 goes into 28 twice, and there IS a period of 14 days, which we don’t use much anymore – the _Fortnight_. I suspect that the Fortnight wasn’t a convenient measure of time – too long for week-like things and too short for longer term things. Besides, it was as easy to say “two weeks” as “one fortnight”. There could conceivably have been three periods of ten days to fit the “solar” month, but I suspect that, having no convenient “quarters”, it would have fallen out of favor pretty fast. ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [June 25, 2001, 1:10pm UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/18 "2001-06-25T13:10:21Z")
> [@](#): > > \*Originally posted by CalMeacham \* > **I agree about the 28 day part. There aren’t too many factors that go into 28. Seven is one of them, and that works out very conveniently, because it lets you have four very identifiable quarters – Full Moon, Half Moon (first Quarter), New Moon, other Half Moon (last Quarter). Dividing further isn’t so easy to do in any case, and when you consider that the time perios would include fractional days it’s clear why they didn’t do it.** As someone else has pointed out, the time from full moon to full moon is more like 30 days. ---
**Author:** ![manhattan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/manhattan/32/7_2.png) [@manhattan](https://boards.straightdope.com/u/manhattan)\ **Post date:** [June 25, 2001, 1:48pm UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/19 "2001-06-25T13:48:21Z")
**Cecil Adams** on the [seven day week](http://www.straightdope.com/classics/a2_166.html). ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [June 25, 2001, 4:29pm UTC](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034/20 "2001-06-25T16:29:14Z")
OK, Cecil is just _reasonable_ about it. A combination of things, he says. Some Babylonian measures the number of days between quarter moon and full, and counts the number of planets in the sky–fudging things a bit–and the twilight zone theme goes off in their head. This has _got_ to be important. Probably lucky too. [Next page](https://boards.straightdope.com/t/seven-day-weeks-and-names-of-days/70034.md?page=2)