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days of the week origin names

Maybe you hate the guts out of Monday.

Do you? I feel you.

Hm, but let me tell you, Monday is not the worst day of the week. Science and research to the rescue!

So, can you tell then, which one is the absolute worst in the week gang?


It is Mr. Tuesday — both in stress and workloads levels. Especially at 11:45 am for working people when stress hits it hard. Tuesday, a typical energy vampire. Wednesday is the best work-wise. Science is backing up this, folks.

More important than any-day hate, tho —have you ever wondered what is the origin of weekday names? Why does a week have seven days? Let’s dig into it.

A bit of Astro history lessons

The names of the days of the week in many languages are derived from the names of the classical planets in Hellenistic astrology, which were in turn named after contemporary deities, a system introduced by the Roman Empire.

The names of the days are in some cases derived from Germanic deities or, such as in Romance languages, from Roman deities. The early Romans, around the first century, used Saturday as the first day of the week. As the worshipping of the Sun increased, the Sun’s day (Sunday) advanced from the position of the second day to the first day of the week (and Saturday became the seventh day).

The seven-day week originates from the calendar of the Babylonians, which in turn is based on a Sumerian calendar dated to 21st-century B.C.Seven days corresponds to the time it takes for a moon to transition between each phase: full, waning half, new, and waxing half.

Because the moon cycle is 29.53 days long, the Babylonians would insert one or two days into the final week of each month.

The Romans also inherited this system from Babylonian tradition, though they didn’t begin using it until the Julian Calendar in the first-century B.C.Up until this point the Romans had used the market day cycle of eight days called “nundinal cycle (labeled A-H)a system they inherited from the Etruscans.

So, the Romans.

They named the days of the week after their gods and corresponded to five planets known to them — plus the Sun and Moon (which the Romans also considered planets).

So let’s take a look at the seven days of the week and how they came to be named.

Greek and Roman gods

Why did the Romans name the week after their gods’ names for the planets? It’s a pretty pagan way of storytelling and it goes like this.

Every night Romans could see multiple changes in the sky. The only explanation of that outwardly celestial design was to make up tales in order to brush off fear. So, wise and respected people saw a connection between their gods and the changing face of the nighttime sky. The ones they were able to see in the sky each night were Mercury, Venus, Mars, Jupiter, and Saturn. Those five planets along with the moon and sun made seven major astronomical bodies so — ding ding ding. You do the math. It was natural to them to use those seven celestial names when the seven-day week was being newly used.

What about the names?

Prepare your Astro and history knowledge.

We’ll start with the easy ones to guess.


The first day of the week was named after the Sun – dies Solis – day of the sun in Latin and later Sunnon-dagaz in old Germanic. It’s easy to see where the English word Sunday comes from here.


It’s similarly easy to see where this weekday name originates too. Monday is the Moon day – dies Lunae in Latin, becoming Mon(an)dæg in Old English.


Whereas most English days of the week retain their associations with the Roman gods, some were substituted for the names of the equivalent Germanic gods, because English truly is a Germanic language.

Tuesday was named for the Roman god of war, Mars, so in Latin was known as dies Martis. However, the Germanic god of war was known as Tiu and the English day of the week is derived from this Germanic god’s name instead, first known as Tiwsday and eventually Tuesday.


Wednesday is Wōden’s day. Wōden, or Odin, was the ruler of the Norse gods’ realm and associated with wisdom, magic, victory, and death. The Romans connected Wōden to Mercury because they were both guides of souls after death. Wednesday comes from Old English Wōdnesdæg.


Jupiter, also known as Jove, is the supreme Roman god and patron of the Roman state. He is the god that created thunder and lightning. Thor is the hammer-wielding Norse god of thunder, often shown riding through the sky in a chariot. And it’s from this Norse god that we see the Latin dies Jovis (day of Jupiter) become Thor’s day and eventually Thursday.


Friday is named after the wife of Odin. Some scholars say her name was Frigg; others say it was Freya; other scholars say Frigg and Freya were two separate goddesses. Whatever her name, she was often associated with Venus, the Roman goddess of love, beauty, and fertility. “Friday” comes from Old English “Frīgedæg.” In Germanic we have Frije-dagaz, later becoming Friday in English. 


We start and finish with easy ones.

Saturn is the Roman god of agriculture, known in Ancient Greece as Cronos. In Latin, we have dies Saturni and it’s not hard to see that Saturday today is still very much Saturn’s day.

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