As a English Canadian who works for a company that was bought by an American company and was force switched to Sunday as the first day of the week….what? Maybe we “officially” or legally have Sundays as the first day but my entire life has been Mondays first. Every calendar I’ve had has been that way as well. It still messes with my mind, even four years later, that at work Sunday is the first day of the week.

What part of English Canada? In Alberta or Ontario (the parts I've lived in, though I was pretty young when I lived in Ontario) I've literally never seen a calendar with Monday as the first day of the week that I can recall.

I think there is a distinction between what people consider the first day of the week and what is printed on a calendar.

The person originally bringing this up referenced printed calendars always having Monday as the first day of the week, so it seems reasonable to use an observation of printed calendars with Sunday as the start of the week as a rebuttal.

Yes this, except it's not even a rebuttle, I'm just genuinely curious where this might be someone's experience because it's very at odds with my own.

I don't honestly care much what people consider the beginning of the week, I try to avoid ambiguity in planning as much as I can anyways for other reasons (this Sunday vs next Sunday for eg.) but I have been tripped up by an unexpected Monday-first calendar in a webapp.

Really?

If someone says "let's meet the 3rd week of April" and you say "ok, let's do Sunday", do you really mean the Sunday in the 4th calendar row?

Given that the first row is usually the end of the previous month: yes ;)

British Columbia.

I'm from Winnipeg originally and considered Sunday the first day of the week. Maybe it's regional or cultural?

It doesn't truly matter or? It's not like you are going to work on sundays. You only realize it with calenders in e.g. Outlook, and long gone TV guides....

It's a little disorienting on booking sites (hotels etc) when the first day of the week isn't Monday.

I once booked a train on the wrong day because the localisation changed part way through my search. (Fortunately I noticed.)

Ah, I disagree: it's disorienting when the first day of the week is on Monday.

Funny how that works, right?

What does it even mean to consider Sunday the first day of the week? What does it change?

In IT, this mess leaks to places it really shouldn't. I've never permanently lived nor worked in native english place, but the amount of time I've seen somewhere in some web app or work outlook weeks starting on Sundays... its maddening, you easily make mistakes in good faith that can have pretty bad consequences, without realizing them.

I think its airbnb that still shows me calendar starting form Sunday. Not cool when you are looking at all those other sites for flight bookings or car rentals, all of them starting from Monday since they respect your locale, and then you book accommodation by muscle memory (since you re-did the searches numerous times as planning decisions about vacation took place), starting at given field for day of the week, only realizing that its moved by 1 day earlier (or later, not sure now). Good if you find out quickly, bad if on the 'arrival' day and your family have nowhere to sleep and its already dark.

I know that this won't ever be resolved mainly due to big egos of those involved, in same way that there will always be those ridiculous feet and inches and miles and absurd conversions between those, on top of fahrenheit madness. Tells something about maturity of mankind...

Every. Single. Calendar.

If you’re in Ontario, you’ll rarely see a paper calendar that isn’t SMTWTFS

Same in Quebec.

Never heard anywhere in canada that don’t have their calendar start on Sunday but I’d be curious to find out otherwise.

Walk into a stationery store in British Columbia and you'll find both options.

Perhaps though that is due to the increasingly globalized world and stationery stores desire to have a lot of varied product from great product makers in Japan, USA and further afield.

I grew up aware that some people considered Sunday the start and others Monday, but didn't seem like there were any real firm rules about it where it mattered. I feel like I saw both being used. I always preferred using Monday as the start of the week.

Edit: Had a quick look at the Vancouver recycling calendar they sent me in the mail: Sunday first.

> Walk into a stationery store in British Columbia and you'll find both options.

Yeah, Staples or a high end paper craft store will have both.

But if you go into one of those popup calendar stores, all the calendars will be SMTWTFS.

"Sat and Sun constitute the weekEND, right?"

"Of course."

"And Sunday is the 7th day, the day of rest?"

"Yeah, that's what they preach at my church."

"What about your workplace?"

"Everybody knows the standard workweek is Mon-Fri. What's your point?"

"Ok, so we're agreed the weekends include Sunday, your Bible says Sunday is the 7th day, and the workweek starts on Monday."

"Yep."

"So printed calendars and day-planners and calendar software should treat weeks as starting on Monday, right?"

"..."

The Bible does not say that Sunday is the 7th day. It says that Saturday, the Sabbath, is the 7th day. And that Jesus rose on the day after the Sabbath, which means it was on the first day of the week. And that's the day most Chistians have adopted as their day of worship. (Except Seventh Day Adventists who keep it, as their name suggests, on the 7th day: Saturday.)

If your church preaches differently, they should read their Bible more carefully.

Seventh‐day Adventists are definitely the most prolific Christian keepers of a Saturday sabbath, but they are not totally alone. The next most prominent groups I can think of are Seventh Day Baptists and Messianic Jews. SDAs are in the tens of millions worldwide, Messianics in perhaps the hundreds of thousands, and SDBs under one hundred thousand.

Although they’re fairly distinct traditions, in my experience each places great importance on religious liberty and separation of church and state, because historically all three groups have faced governmental persecution from blue laws. SDAs go so far as to believe Revelation’s mark of the Beast refers to a blue law to come in the future.

Messianics also have been known to face religious persecution in Israel. To the extent Christianity is viewed with mistrust by Judaism due to Christendom’s history of persecuting Jews, Messianic Judaism is further seen as an attempt by Christians to co‐opt or corrupt Jewish practices.

(Another fun fact: Seventh‐day Adventists hyphenate their name, but Seventh Day Baptists don’t.)

And not event that far, sabbath (Saturday) is determined to be the 7th day of the week at the start of Genesis.

We also have "bookends" which go on both sides of the books they support. That's kinda how I see "weekends".

"Sat and Sun constitute the weekEND, right?"

It's called a bookEND only if it's to the right of the row of books. If it's to the left (for books in an RTL language), we call it a bookSTART

There are two bookends in every matching set - one for each end of the row of books.

6-day work weeks are still common in agriculture, and the Bible is silent on what the exact weekday the sabbath lands on. Some people really argue that it's supposed to be Saturday, but traditionally Jesus's resurrection is said to have happened on Sunday, so most Christian churches went along with that.

My own personal opinion: it matters not what day you consider to be the sabbath, but it does help when a community agrees on a day and goes along with it. So for me, Sunday it is. (It also doesn't matter how a calendar is printed; it could start on Wednesday for all I care. It'd be weird, but it wouldn't change anything.)

The day of the sun, or the Lord's day, is not the 7th day sabbath, it was declared by the Catholic Church to supersede the Sabbath and celebrate the resurrection instead.

In saying “the Sabbath . . . has been replaced by Sunday” (CCC 2190), the Church does not dismiss the significance of the Sabbath. The Catechism reminds us, “Sunday is expressly distinguished from the Sabbath which it follows chronologically every week” (CCC 2175).

https://www.catholic.com/magazine/print-edition/the-lords-da...

As for which day is the 7th, you can check with descendants of the good book's authors, still around, and still keeping count. The Jewish faith hasn't lost track.

Thanks, that's good info :) I definitely have new things to study and ponder about.

I'm of the Latter-day Saints tradition and we basically use Lord's Day and Sabbath interchangeably, though I'm speaking anecdotally and from casual use. I may very well be using it incorrectly!

IIRC it was very common for early Christians, who were mostly Jews initially, to go to temple on the Sabbath (Saturday) and then have their own meetings on Sunday, as they didn’t consider them separate.

I think we can trust the Jews to have kept the Sabbath fairly consistently. The Christians literally changed their reserved day of the week in honour of Jesus' resurrection. Luckily the fact that this was the day after the sabbath is completely unambiguously pinned down in the Bible.

The Arabic/Islamic calendar starts at Sunday because the weekend is Friday and Saturday. In Islam, the weekly congregation (mass equivalent) takes place on Friday around noon.

Switched to a browser to comment exactly this.

Growing up in Saudi Arabia, we started our work week on Saturday, with Wednesday being the last day of the work (school for me) week. It took me a long time to transition over to think about Saturday/Sunday as the days off. I still get random pangs of excitement on Wednesday thinking it’s the end of the week if my brain hasn’t warmed up.

I believe this is still the case in the gulf states and I would assume other Islamic countries.

You made me think of Malaysia, Brunei, Indonesia: All are Islamic majority in Southeast Asia. I Googled and look what I found: "Identify the first day of the week based on the locale"

Ref: https://help.salesforce.com/s/articleView?id=000338932&type=...

The entries for Indonesia don't make sense to me.

> A quick check of Wikipedia suggests Arabic, Portuguese and Vietnamese, all use number-based systems to name the days of the week, and they are indexed from Sunday = 1.

I can confirm that in Hebrew, the name for Sunday translates into "First Day", Monday into "Second Day", etc. Except for Saturday, which is Shabat.

Shabbat (apart from meaning "rest") is also generally accepted as deriving from the Hebrew word for "seven", which is "sheva". And Shabbat is sometimes referred to in Hebrew as "yom shvi-i" ("seventh day").

Citation needed.

Klein Dictionary gives the etymology of שַׁבָּת as derived from שׁבת (to rest). I also found references suggesting the origin is with the Akkadian šapattum, the 15th of the month, but none related to שׁבע (which originates in Proto-Canaanite).

היּוֹם הַשְּׁבִיעִי (note the definite form!) is how Saturday is referred to in Genesis 2:2-3, without actually having the name שַׁבָּת. There's a some discussion about why שַׁבָּת isn't mentioned there as a name for the day, but regardless, your comment is the first time I read of the etymology of שַׁבָּת deriving from שׁבע.

I know it's not a reliable source by itself, and it lists no citations for the sentence in question, but FWIW, I based my answer on https://en.wikipedia.org/wiki/Shabbat#Etymology :

> Other related words are ... to sheva (שֶׁבַע) meaning seven, as Shabbat is the seventh day of the week ...

Trying to read this on Android (in Materialistic) was fascinating, each line containing a Hebrew (?) word caused some of the words around it to switch places, but the words themselves are fine??

Unicode TR-9 is a hard beast to tame.

In Portuguese, Monday through Friday translates to something like “Second Fair” through “Sixth Fair”¹. Saturday and Sunday aren’t numbered.

¹ “Fair” as in “a gathering of stalls and amusements for public entertainment”.

Similar in Arabic, except Friday is juma and Saturday is sabat.

> The week is still popularly understood to start on Sunday in English Canada

As an english canadian (alberta), i have never in my life heard of people considering sunday the first day of the week.

Edit: appearently people are talking what is printed on calendar. I consider that to be a separate thing. If you asked me to list the days of the week in order i would start on monday, which is a totally separate question from the layout of a printed calendar.

> which is a totally separate question from the layout of a printed calendar

I have no strong preference on Monday/Sunday, and I don't think either is inherently more logical than the other. However, it would be illogical, whether Sunday or Monday first, to have the 7th and last day of the week, laid out as the first column on the calendar.

I like to have my two weekend days next to each other since they are a fairly discrete chunk of time in my mind and planning.

How would the colloquial understanding of the first day of the week get divorced from what's printed on calendars, though? I feel like one should inform the other, no?

Out of curiosity, if you have a calendar app on your computer, does it start with Sunday or Monday?

Majority of calendars in Japan are starts from Sunday but IMO now people think week starts from Monday. It's relevant to whether people work (or went to school) on Saturday or not (so two consecutive holidays). Some research shows that old ages (who worked on Saturday) tend to think it starts from Sunday.

Calendars tend to follow traditions, and the difference isn't much matter. Also computer apps are tend to follow the US culture since US dominates the industry.

I would guess that in a globalized world, stuff printed in the united states doesn't always match local culture.

Portuguese name weekdays by numbers ex Monday, Segunda-feira (Second Market), but I don't think anyone assumes Sunday as the first day.

And I leave the "market" for someone who still didn't have enough of this rabbit hole.

> I don't think anyone assumes Sunday as the first day.

That is not up to assumptions, but to conventions and arbitrariness. You find both conventions among Portuguese speakers, but mostly domingo/Sunday as the first day of the week.

A good way to check this is to websearch pictures for "calendário em português", and look for the first column of the calendar. Most will have D/Dom (domingo/Sunday); however a large minority will have S/Seg (segunda-feira/Monday) instead.

>And I leave the "market" for someone who still didn't have enough of this rabbit hole.

It's mostly a fossilised meaning.

Latin "feriae" originally meant holidays, holy days, vacations, and the likes; that's why the clergy¹ chose "feria" for the weekdays, as you'd be praising their god instead of the Pagan gods². However, already in Late Latin, this backformation also meant "fair"³. In Portuguese that second meaning eventually evolved to "street market", likely due to influence of the names of the days of the week - you don't work in domingo/Sunday or sábado/Saturday, but you gotta work and sell stuff in the "dias de feira" (feira days).

1. This clergy intervention was done in Latin. This is visible for the name of Tuesday being terça-feira ← tertia feria instead of *terceira feira (third holy day).

2. The traditional names for Monday to Friday were lues, martes, mércores, joves, vernes. Ecclesiastical interference got rid of the names for Sunday and Saturday early on, but if Portuguese inherited the Roman names they'd be something like "soes" and "sadurnes" respectively.

3. In fact that's where English got the word "fair" from. At least when it comes to those fancy markets/exhibitions/etc.; not to be confused with the homophone "fair" for just, beautiful, etc., as this one is native and unrelated.

Russian is similar to Portuguese, albeit off by one.

Monday = Segunda (second) = понедельник (start of the week)

Tuesday = Terça (third) = вторник (second)

Wednesday = Quarta (fourth) = среда (middle)

Thursday = Quinta (fifth) = Четверг (fourth)

Friday = Sexta (sixth) = пятница (fifth)

So I guess Russians have no doubt as to when the week starts.

On a side note, it's not 100% clear (to me, at least) that the word for Monday (ponedelnik) means "per week" or anything about the week per se.

In Russian the word for week is "nedelya", so "ponedelnik" does seem to naturally tie into that. But the word for Sunday in Russian is "voskresenie" (literally means resurrection). Notice this! Every religious word used in non-religious context is suspicious!

If we examine Bulgarian, the week is called "sedmica" (sedm == seven). And Sunday is called "nedelya" (I perceive it as "ne delya" === "no work").

Thus, in Bulgarian the word ponedelnik becomes like "the day after Sunday", rather than "the day starting every week".

Now going back to the Sunday resurrection theme, it's obviously of religious origins, so I dare assume that it may have replaced something that was already there (like nedelya). And then I imagine the people still wanted to keep the word around, so they started using it to mean "week" instead of "Sunday".

If so, then it would make sense that ponedelnik just means "post Sunday".

[The above is just a pet theory I haven't spent any time on, so I'm not guaranteeing its legitimacy]

This is correct, "nedelya" (no-work) is the common Slavic word for Sunday. The Russian variant is a more recent invention.

Note that this off-by-one is exactly the difference between Jewish/Biblical-based weeks, where the Sabbath is clearly the last day of the week (based on Genesis, the day when God rested), and more "revisionist" Jesus Christy-based weeks, where the day that Christ was resurrected is considered more important than the Sabbath and takes its place as the end of the week.

While the majority of Christians meet on Sunday and consider it the “new” Sabbath or the fulfillment of the Sabbath, in commemoration of Jesus’s resurrection, how does that relate to restructuring the week so Sunday is the last day? The Bible is clear that Jesus was resurrected on the first day of the week, the day after the Sabbath.

Matthew 28:1 (NIV): “After the Sabbath, at dawn on the first day of the week, Mary Magdalene and the other Mary went to look at the tomb.”

Mark 16:1–2 (NIV): “When the Sabbath was over, Mary Magdalene, Mary the mother of James, and Salome bought spices so that they might go to anoint Jesus’ body. 2 Very early on the first day of the week, just after sunrise, they were on their way to the tomb…”

Luke 24:1 (NIV): “On the first day of the week, very early in the morning, the women took the spices they had prepared and went to the tomb.”

John 20:1 (NIV): “Early on the first day of the week, while it was still dark, Mary Magdalene went to the tomb…”

I believe, though am not sure, that once Christians stopped observing the Jewish Sabbath and instead resting on the Lord's day, it also became natural to consider it the end of their week, instead of the beginning.

Then why does the US, a very young culture compared to Europe, universally consider Sunday the first day of the week? Calling Sunday the seventh day must be a very recent development.

The USA was founded and its culture heavily influenced by very deeply religious Protestants. While by the time of the founding of the USA, Sunday was decently well established as the seventh day in both Catholicism and Orthodoxy, most protestants were Bible originalists.

I believe that they resurrected the practice of considering Sunday as the first day of the week, based on the Old Testament tradition. Just like New Earth Creationism is in fact a relatively recent phenomenon driven by a renewed interest in literal interpretations of the Bible, that had long since been superseded in Catholic scholarship.

Actually Orthodoxy is arguably more inclined to treat Sunday as the first day of the week as witnessed by the Greek language.

There are also several patristic writings that conceptualise Sunday as the eighth day of creation, i.e. the resurrection perfecting and completing creation (this also suggests that literal seven day creation wasn’t taken that… er… literally back in the day).

Well, in Polish, Monday is poniedziałek, which means "after Sunday" (Sunday is "niedziela") and not "start of the week" and it looks analogous in Russian...

That sounds quite sensible. From memory, our (en_GB) weekdays are named like this:

Monday -> Moon day

Tuesday -> Tiw's day (Norse)

Wednesday -> Woden's day (Norse - Odin - chief god, one eye, two ravens)

Thursday -> Thor's day (Norse - god with a massive hammer) Friday -> Freya's day (Norse, rode a chariot drawn by cats)

Saturday -> Saturn's day (Roman, also: Saturnalia is the winter festival that eventually became Christmas)

Sunday -> Sun day

> That sounds quite sensible. From memory, our (en_GB) weekdays are named like this:

Spanish and English follow a similar day naming convention.

But the god's name needs to be translated from Norse Mitology to Roman Mitology first [1]

Lunes/Monday -> Moon/Luna

Martes/Tuesday -> Tiw/Mars

Miercoles/Wednesday -> Woden/Mercury

Jueves/Thursday -> Thunraz/Jupiter

Viernes/Friday -> Frig/Venus

Sábado/Saturday -> Saturn/Saturno

[1] https://en.wikipedia.org/wiki/Interpretatio_graeca

With the exception of Saturday. Tacitus associated the Hebrew sabbath («sábado») with Saturn, but the word for the day itself is not «saturno» as it would be if it were like English.

I'd always thought (though I don't have a specific source I can recall), that the seven days of the week was drawn from the seven non-fixed celestial bodies visible ot the naked eye: the Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn. The planets were frequently associated with and named after deities, so the days of the week also have the names of deities.

Friday literally means Day of Frigg (Old English), referring to Frigga, the wife of Odin. Yes, Freya is believed to be the same goddess as Frigga, but the day is named after Frigga not Freya.

Thurday would probably be 'Þunor's Day' instead of Thor as it's Old English :)

They absolutely do in Portugal - I’ve been tripped up by “see you next Sunday” when they meant “see you this Sunday”.

> but I don't think anyone assumes Sunday as the first day.

You can get any calendar from a Portuguese speaking country to see they do.

Segunda-feria supposedly comes from Church Latin where it means 'second weekday'.

> Sunday = 1

Animals. Absolutely barbaric.

Everybody knows we should index lists starting at 0. /s

Well by struct tm, Sunday is 0. And months start at 0. And the day of the month starts at 1!

I remember years ago that Larry Wall said about Perl 5->6 upgrade: "We can fix some broken things." This was an item on his big list.

Time to start a movement to consider saturday the as the beginning of the week!

I remember seeing API that accepted both 0 and 7 as Sunday.

crontab uses this approach, for example.

> Then there's Swahili: Saturday = 1 and Friday = 7. Though personally, I believe Sunday is the 0th day of the week.

The cron way, where both 0 and 7 means sunday

> .. considers Sunday to be the first day of the week

How can the first day of the week happen in the middle of the weekend!?!

Weekends? Weekends are... the ... ends of the week. When you build a bookshelf, do you do:

<stack of bricks> <book> <book> <book> <book> <book> <stack of bricks>

or do you do:

<book> <book> <book> <book> <book> <stack of bricks> <stack of bricks>

When you want to know how your friend spent the previous Saturday and Sunday, do you ask:

"How was your weekend?"

Or do you ask:

"How were your weekends?"

When you purchase bookends, you get two, one for each end of the bookshelf.

A week is not a bookshelf, it's a snake. Does a snake have one end, or does it have two? Does a dog have two tails and two butts?

Weeks are not snakes, either. They're continuous, forever. Do snakes line up mouth to tail forever?

When they're stressed or ill, yes:

- https://www.iflscience.com/stressed-out-snake-eats-itself-24...

- https://en.wikipedia.org/wiki/Ouroboros

A week is not a snake. Each week is discrete and a different week from every other week.

Both ends of the week are the weekend.

One is the starting weekend, and the other the ending weekend.

Right, I (in the US) always figured "end" in the word "weekend" was akin to the two ends of a line segment, the two ends of a bar, etc.

To instead think of "end" in the word "weekend" as the opposite of "start" is to use a completely different definition of the word "end".

I wonder if "weekend" therefore has two definitions, given the split dependency.

It feels to me that for "end" to be used as the two ends of the week, it would be weekends (plural), not weekend (singular).

Considering that the word is from the British and the fact that the week ends with Sunday there, that can't be it. It would also be weekends, not weekend if there was multiple ends. The upcoming weekends doesn't mean Saturday and Sunday in the US... It occurs over a time period of at least one whole week into the future...right?

Sunday being the first day of the week came long (as in thousands of years) before the weekend was invented (which is a very recent development).

The same way all the other illogical things happened: random cultural legacy.

Why would you expect the week start day to be any different?

Because the week has two endpoints: the initial day of the week and the final day of the week.

> A quick check of Wikipedia suggests Arabic, Portuguese and Vietnamese, all use number-based systems to name the days of the week, and they are indexed from Sunday = 1. But yes, the other is more common. Most of the Slavic languages, and Chinese, among others, use indexed from Monday = 1.

For portuguese the name being number based has nothing to do with when the week starts, portugal is historically a very christian country and always had the week end on sundays, "and on the seventh day he rested", in both casual/formal speech and formally with calendars and such, saturday and sunday are always put at the end.

The names being numerical was because that's how the names were named during Holy Week (the week that ends with easter sunday), christians were supposed to rest and not work during that week, so sunday was the first rest day, monday the second rest day, etc. which is what the names mean, some people today think it means fair as in state fair/market, e.g. monday is "segunda-feira" = "second fair", but it actually means something closer to holiday, the modern portuguese word being férias.

The reason it took over was basically because the church said so, the old names were still based on old gods and the new nomenclature was adopted for all weeks instead of being Holy Week exclusive.

I guess if the aliens landed in portugal that would be another thing to add to the thread :)

All Christian denominations agree with the Jewish ones: God rested on the seventh day - The Sabbath, or Saturday. Jesus was then resurrected on the day after the Sabbath, the first day of the Jewish week, which became the Lord's Day in many European languages (Domenica, Domingo, Duminică etc). It was quickly understood as a non-working day, a day of religious celebration, but it was still the first day of the week.

Now, since Jesus and his resurrection are much more important in Christianity than the creation of the world, the Sabbath began losing its importance, and so renumbering the week started making sense, but was a contentious religious and political issue for a long time. Of course, having two rest days, and one of them being based on Jewish customs in a quite anti-semitic medieval Europe, played a part as well in wanting to change things.

I'm relatively sure that the Portuguese week day names are based on the original Jewish week.

> A quick check of Wikipedia suggests Arabic, Portuguese and Vietnamese, all use number-based systems to name the days of the week, and they are indexed from Sunday = 1.

Vietnamese only numbers the days of the week from Monday to Saturday, with Monday = 2 and Saturday = 7. Sunday has its own name that isn't a number and is always put at the end of the week.

I thought that that in Slavic languages Sunday would be the first day of the week, since the Polish for 'monday' means 'after sunday'.

EDIT: got 'monday' and 'sunday' the wrong way round

In Russian, Sunday is "Resurrection Day" and Monday is "The Thing concerning Not-Doing being in the Past-Perfective Tense" (po + ne+del + nik)

It looks like Polish is similar except that Sunday is "Not-Doing"

In Polish, Sunday is „niedziela”, and Monday is also „poniedziałek”, so it actually makes more sense than in Russian :) I suspect “niedziela” («неделя») was the original, proto-Slavic word for the day of the week, as some variations of it are used for I think all Slavic languages except Russian, who at some point decided to rename it to celebrate Resurrection.

Not-Doing can be a false alias: the week is nedelya and ponedelnik may thus mean "one going with the week*, i.e. starting it.

Altough I'm not sure since the sibling proto-slavic explanation makes much sense. Fun fact: slavic languages split off in medieval times when the calendar and the week were already thorougly taken care of.

Only in Russian.

In other Slavic languages it's mostly some form of ty + djen' (Polish tydzien Croatian tjedan Czech týden Belarusian тыдзень Ukrainian тиждень). But see Bulgarian (седмица seven-thing (fem.)).

I suspect (without evidence) that, in Russian, it's referring to Sundays as a way of reckoning weeks.

week:Sunday :: year:summer :: month::moon. Cf. "When I was but 10 summers old", "Many moons ago", etc.

That would fit with the use of the archaic word for Sunday as well.

Ponedelnik etymologically means the day after the not-doing day. Nowadays the connection is lost because Sunday is no longer called “nedelja”.

Depends ;). In Croatia its still called nedjelja (Sunday) and ponedjeljak (Monday).

Hmm, and the week is the not-done-thing?

Etymology is hard, the week “ne-delya” could be understood as something that cannot be divided, “not-divisible”. I am not sure which one is correct.

nope, monday is „after sunday”

Thanks for catching that, I got my English the wrong way round.

> The week is still popularly understood to start on Sunday in English Canada

Interesting. How does software (e.g. Google Calendar) display weeks when in en_CA localization?

Most software I can think of lets you configure it independent of the locale.

In Chinese the weekdays are also numbered and indexed to Monday: Monday = 星期一 xingqi yi (1), Tuedsay = xingqi er (2), all the way down.

Japanese calendars start the week with Sunday as well.