In a Word: My Gods! What Day Is It?

We get the names of days from the planets, which get their names from the gods, but which gods and why?

Sticky notes with the days of the week written on them

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Managing editor and logophile Andy Hollandbeck reveals the sometimes surprising roots of English words and phrases. Remember: Etymology tells us where a word comes from, but not what it means today.

One consequence of always working from home is that the days blur together even more than usual. I’m sure I’m not alone when I find myself legitimately trying to work out whether it’s Wednesday or Thursday. But that wondering opened up a new line of thought about why the days are called what they’re called. And why is it even that our weeks are seven days long and not six, or eight, or thirteen?

The seven-day week goes back millennia, at least to the ancient Sumerians, and it makes perfect sense if you think about it: Seven days is approximately the time it takes for the moon to move from one phase to the next. The spread of Jewish and Christianity tradition certainly helped to solidify this concept as well: God created the world in seven days, not thirteen.

Ancient Rome, however, relied on an eight-day nundinal cycle that they inherited from the Etruscans. Not until Julius Caesar made other massive adjustments to the annual calendar did the seven-day week really start to take hold in Rome. They named those days of the week after the seven known planets (which included the sun and moon), which were, in turn, named after Roman gods.

As the Roman Empire expanded, it took these names into northern Europe, where the Roman mythology behind the days’ names was filtered through Norse and Germanic mythology. Those names found their way into Old English and then evolved into the days of the week we love today, even if we don’t know which day it is right now.


The first day of the week comes from the Old English sunnandæg “day of the sun,” a literal transcription of the Latin dies solis. As Christian influence spread across Europe, English stuck with the planetary reference, while other languages turned Sunday into the “day of the Lord,” dies Dominicus in Latin, which became, for example, domingo in Spanish and Portuguese and dimanche in French.


In Old English, mōndæg, a contraction of mōnandæg, literally meant “day of the moon” — Máni was the Norse personification of the moon. It traces back to the translation of Latin Lunae dies, which is the root of the name of this day in most Romance languages, like Italian (lunedi) and Spanish (lunes).


In Rome, the third day of the week was named for the god of war, Mars, and most Romance languages kept that association: It’s mardi in French and martedì in Italian.

Tyr (Tiw or Tiu in Old English) was the original supreme deity of ancient Germanic mythology, more akin to Jupiter (Zeus) than Mars. But in that old mythology, Tyr was also, as Encyclopædia Britannica puts it, “the god concerned with the formalities of war,” and so he was associated with Mars, and the day was named tiwesdæg after him.


The hardest day of the week to spell was even worse in Old English: wodnesdæg “Woden’s [Odin’s] day.” Odin was the king of the Norse gods, like Tyr more obviously associated with Jupiter than any of the other Roman gods.

In Latin, the day was dies Mercurii, for the god Mercury, hence mercredi in French and miércoles in Spanish. How did we get from Mercury to Odin? They do share one characteristic: Both are psychopomps, beings who transport the souls of the dead to the afterlife.


The fifth day of the week was, in Old English, þurresdæg, a contraction of þunresdæg. That first character, þ, is called a thorn. It was a letter in Old English that was eventually replaced by th — in large part because early printing presses were manufactured in places that didn’t have that letter in their alphabet. Þunor is more commonly known as Thor today (also the source of the word thunder), and þunresdæg, Thursday, is “Thor’s day.”

In Rome, we finally get to the day named for the king of the gods, Jupiter aka Jove: Jovis dies “Jove’s day” (itself a loan translation of the Greek dios hemera “day of Zeus”). Of course, Thor wasn’t the king of the Norse gods, but both Thor and Jupiter/Zeus were their respective gods of thunder.

Romance languages continue the link to Roman mythology: Thursday is giovedi in Italian and jueves in Spanish.


In Norse mythology, Frigg was Odin’s wife. Scholars have long argued about whether Frigg and Freya (or Freyja) are completely separate deities or they began as a single goddess who differentiated into two beings as the mythology grew. (For more adventures in blurred lines between goddesses, read my earlier column “Trivia Three Ways.”) This ambiguous separation plays a role in the source of Friday, which was called in Old English frigedæg “Frigga’s day.”

In Latin, the sixth day of the week is dies Veneris “day of Venus” — which has evolved into, for example, vendredi in French and vineri in Romanian. Venus, of course, is the counterpart of Aphrodite, the Greek goddess associated with love, beauty, and fertility.

Friday is named after Frigga, it’s clear, but Freya is the Norse goddess associated with love, beauty, and fertility — that is, the goddess who most closely mirrors Venus.


In Rome, the last day of the week was Saturni dies, “Saturn’s day.” Perhaps because the mythology of northern Europe didn’t have an obvious analogue to Saturn (Cronus in Greek mythology), a new god wasn’t assigned to this day, and it became, in Old English, sæternesdæg. (Some Norse languages did draw from an older tradition, giving Saturday a name that translates as “bath day.”)

But in a strange twist, Europe’s romance languages did veer away from the mythological association, reaching back to Hebrew. Sabbath became sábado in Spanish and Portuguese, samedi in French, and sabato in Italian.

Featured image: Shutterstock

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  1. As long as it’s the day I get my unemployment money (with the extra $600 added), the $1,200.00 stimulus check and my next issue of the Post, Monday through Saturday are just fine!

    No, this was an interesting study on the seven days of the week and how they came about. The only days I could connect with something were Saturday (Saturn), Sunday (the sun) and Monday (the moon). Speaking of Saturn (the car) I was surprised when General Motors announced they were dropping it about 10 years ago. It was one of their more successful import fighters, and newest divisions having started in the ’90s. Their bean-counters who run everything (into the ground) I guess thought it was a good idea—like starting up Hummer.


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