Etymologies of the names of the days of the week

Etymology of weekday names in English and French


This page was originally composed as eight separate posts, seven of which each gave the etymologies of the English and French name for the corresponding day of the week and one of which gave a brief history of the seven-day week. I have combined these posts into a single page with a small amount of re-editing.

If the order in which the days appear – starting with Saturday and ending with Friday – instead of a more conventional ordering starting on Sunday or Monday, I can only say that that is the order in which I wrote the original posts. There’s no harm in being unconventional from time to time!

Saturday and Samedi

Today is Saturday, the day when in normal times we would be thinking of taking a trip somewhere, whether out of town or to some interesting area within Greater London. That is not possible at present and we must find other ways of entertaining ourselves.

Thinking about Saturday, and its name, brought to mind its French equivalent samedi and the fact that while the names of the months are similar in both languages, the names of the days of the week are different. There was only one way to proceed: by looking up the etymology of these words!

I will look at the name of Saturday today and deal with the others later. In the meantime, here is a list of the days of the week in English and French.

English French
Saturday samedi
Sunday dimanche
Monday lundi
Tuesday mardi
Wednesday mercredi
Thursday jeudi
Friday vendredi

The first thing the English learner of French notices is that whereas Englsih spells the names of the days of the week each with a capital letter, French eschews capitals, treating the day names like any other common nouns. As far as I can tell, however, this is merely a cosmetic difference without any deep significance. In this context, we might remark that while English capitalizes adjectives of nationality such as British, French , German, etc., French spells them with lower case intials, e.g. britannique, français, alemand, etc.

The English name Saturday derives from the Old English (i.e. Anglo-Saxon) Sæternes dæg. The first is the genitive (possessive case) of Sætern, the name of the planet Saturn, while the second is the ancestor of our word “day”.

Saturday is, then, “the day of the planet Saturn”. That may seem obvious but it is a little odd. Two other days of the week celebrate the sun and the moon, respectively, and the remaining four days of the week refer to gods or goddesses. The sun and the moon are very noticeable residents of the sky, and acquired the status of god or goddess in most cultures, whereas the planet Saturn is a relatively obscure object. How did it come to occupy a place among the days of the week?

In Roman religious mythology, however, Saturnus was a god, in fact the god of sowing seed, so perhaps this feeling of its godlike nature somehow moved with the name into the language of the Anglo-Saxons and secured it the place that it has occupied ever since.

In French, as we shall see, some of the planets in their aspect as deities are also memorialzied in the names of the days of the week but samedi is not one of these. In Latin, the names of the days comprised two words, the noun dies, meaning “day” and another word to individualize it. As English learners of French soon discover, French has a habit of not pronouncing the final consonant or consonants of a word and it takes little stretch of the imagination to see how dies became shortened to di.

The early Christians took over many customs from the Jewish religion until, for various reasons, they felt the need to differentiate their own faith from it. Until Constantine the Great in AD 321 declared Sunday to be the Christian day of rest, Christians had observed the sabbath on Saturday as did the Jews. The French name of that day of the week reflects that fact.

The ordinary folk of the time probably used the word sambatum to name the sabbath and so Saturday was to them sambati dies, “the day of the sabbath”. One can easily see how this would become shortened to “sam’ di”, phonetically transcribed as samedi.

The names of the days of the week are but one set of words that when examined closely can be seen to contain distilled vestiges if our historic past.

Origins of the seven-day week

Continuing my meditations on the names of the days of the week in English and French, which I began in my post Saturday and samedi, it occurred to me to wonder why we have weeks of seven days at all.

It seems that the seven-day week was probably settled by the Babylonians about 4,000 years ago. They might have chosen this rather awkward prime number seven for the length of the week for two reasons. The first is that the number seven was sacred to them – a vague memory of which perhaps still persists today when people think of the number seven as “lucky”. The second reason has to do with astronomy.

The Babylonians were accomplished mathematicians and also avid sky-watchers who virtually invented the science of astronomy. Their calendar defined the year as twelve synodic (lunar) months, making it about 354 days long. To reconcile it with the solar year used in agriculture, they added extra days as necessary.

The Babylonians were meticulous at record-keeping and this in itself enabled them to make a number of discoveries. For example, they discovered the Saros cycle of the moon. This lasts for about 18 years, 11 days and 8 hours during which lunar events recur almost exactly. Thus they were able to predict lunar and solar eclipses long before they actually happened.

The Babylonians knew that while the stars remained in fixed positions, there were certain celestial objects that moved. These included occasional visitors such as comets and meteors but the most important ones were the sun, the moon and the five known planets. Here are their Babylonian names, shown with their English equivalents:

Sun Moon Mars Mercury Jupiter Venus Saturn
Shamash Sin Nergal Nabû Marduk Ishtar Ninurta

What would be more natural for these gifted astronomers than to name the seven days of the week after these seven celestial bodies which they associated with their gods?

The Greeks and the Romans took over this ancient week of seven days, substituting their own day names. The Romans named the celestial objects after their own gods and goddesses. The sun and the moon were seen as deities in their own right while the planets were designated as Mars, the god of war; Mercury, the messenger of the gods but also the god of commerce; Jupiter or Jove, in ancient times the god of the sky and thunder but to the Romans the chief of the gods with a propensity for casting down thunderbolts on people who angered him; Venus, the goddess of love and beauty; and Saturn, the god of sowing and agriculture in whose honour the festival called Saturnalia was held every year on December 17th.

The Romans took their calendar with them to the lands that they conquered and occupied. This included Britain but, whereas France and other old colonies of Rome continued using (and modifying) the Latin language and the Roman day names, in Britain, invading Scandinavian and Germanic tribes replaced the Romans and took over as the ruling class. Their language and culture became dominant. This of course affected, among other things, the names of the days of the week. Exactly how it affected them we shall see in due course. The seven-day week, however, was retained and is with us still.

Sunday and dimanche

Continuing with my series of posts on the etymologies of the names of the days of week in English and French, today’s episode is about Sunday or, in French, dimanche.

To start with, here is a quinquelingual list of the names of the days of the week. I have included the Latin day names in this list because they seem to be at the root of those names in later languages, even when it might not be obviously the case, and the Babylonian names because, after all, the Babylonians started to whole thing off!

English Babylonian Anglo-Saxon Latin French
Sunday Shamash Sunnandæg dies Solis dimanche
Monday Sin Monandæg dies Lunae lundi
Tuesday Nergal Tiwesdæg dies Martis mardi
Wednesday Nabû Wodnesdæg dies Mercurii mercredi
Thursday Marduk Ðunresdæg dies Iovis jeudi
Friday Ishtar Frigedæg dies Veneris vendredi
Saturday Ninurta Sæternesdæg dies Saturni samedi

The Romans, following the trend set by the Babylonians, named two days after the sun and the moon in their aspects as god and goddess, respectively, and the remaining five days after four male gods and one female goddess. These names are also the names of five of the planets which were thought to represent those deities.

As you can see from the above table, the Romans named the first day of the week after the sun – dies Solis, literally “day of the sun”.

The Saxons and Norse invaders of Britain simply took the Latin name for Sunday and translated it into their own version, Sunnandæg, which consists of two words, Sunnan, the genitive (possessive case) of sunna, “sun” and dæg, “day”.

The Anglo-Saxons also had another word for sun which was perhaps a borrowing from the Latin. This was sol, and the notable thing about it is that it was feminine, not masculine as the sun is usually considered in languages which accord it a gender. The word sol was seldom used, however, and we can ignore it for present purposes.

The Roman name, as we saw is dies Solis. The first word, dies, means “day”. The interesting thing about that is that it seems to have been derived from the same root as the word deus (“god”) and and our word deity. The Romans had a long tradition of sun worship so the latter’s position among the days of the week is not surprising.

In the Eastern Roman Empire founded by Constantine and centred on the city of Byzantium, the sun was revered as Sol Invictus, “the Unconquerable Sun”, and the highest value monetary coin, made of gold, was also called a sol.

To Christians, dies Solis became the day of rest and, as we saw in Saturday and samedi, in AD 321, Constantine made Sunday the sabbath in place of Saturday.

As Christianity asserted its position as the state religion, Sunday became known as dies Dominicus, the adjective meaning “pertaining to the master”, so that the “day of the sun” became “the Lord’s Day”.

In the mouths of the people of Byzantium and the countries once conquered by Rome where Vulgar Latin (meaning “the language of the people”) was spoken and was evolving into what would later be known as separate languages such as French, Spanish, Italian, etc., the awkward phrase dies Dominicus, sometimes mutated to dies Dominica, went through a series of changes, too many to be listed here. Each group of people gave it their own spin and it became dimanche in French, domingo in Spanish, domenica in Italian and dozens of other variations in other languages and dialects.

The English, whether Christian, pagan or anything else, went on calling it Sunnandæg, which easily smoothed itself out to become the modern Sunday.

Monday and lundi

We have already discussed the origin of the names of Saturday, samedi, and Sunday, dimanche, and these are in fact the most complex of the seven day names. The remaining seven are relatively simple, being named after gods or the planets that represent those gods.

In all of the languages previously cited, the day following Sunday is dedicated to the moon. As a reminder, here is a chart of the names of Monday in all those languages:

English Babylonian Anglo-Saxon Latin French
Monday Sin Monandæg dies lunae lundi

The Romans named this day after the moon, whose name in Latin is luna. This is a feminine noun and the genitvie (possessive) form is therefore lunae, giving dies lunae or lunae dies, “day of the moon”, as the day name in Latin. (The Babylonian Sin is also feminine.)

In Vulgar Latin, the Latin spoken by ordinary people in France, this “correct” Latin phrase mutated into lunis dies, perhaps because the genitive forms of the names of the other gods/planets also ended in -is, for example martis dies, the day named after the god/planet Mars.

As time passed, the speech of the people gradually evolved into new forms and the exact syntax of the day names ceased to be important. Thus lunis dies changed into various forms such as lunedi and the modern lundi.

The Germanic and Scandinavian peoples frollowed the Roman pattern of day names except that they replaced the Roman gods with their own. The moon, of course, was common to all of these cultures. In Anglo-Saxon, the word for moon has two forms, mona and mone which are masculine and feminine, respectively. However, their genitive forms coincide as monan. Thus this day was known to the Anglo-Saxons as Monandæg which happens to be a word-for-word translation of the Latin lunae dies.

In Middle English, the word became Monedai (‘g’ in Anglo-Saxon was often pronounced like a modern ‘y’) and this eventually mutated into the modern Monday whose meaning “moon day” is still easy to see.

Tuesday and mardi

Continuing our survey of the etymology of the names of the days of the week, the first day of the week to take its name from a god and his associated planet is Tuesday, or mardi in French.

As a reminder, here are the names of this day of the week in the five languages previously discussed:

English Babylonian Anglo-Saxon Latin French
Tuesday Nergal Tiwesdæg dies Martis mardi

The Babylonian god Nergal was worshipped widely throughout ancient Mesopotamia and his symbol was the lion. He was held to be the god of death, war and destruction but, perhaps counterintuitively, his aid could be sought for protection and assistance. He shows an obvious resemblance to the Roman god Mars and the Germanic Tiw. For more information, see the Wikipedia article on Nergal.

To the Romans, the red planet represented Mars, the god of war and consequently, the patron god of the army. For more on this, see the Wikipedia article on Mars.

In Latin, the name of this god was the same as in modern English, Mars, and the genitive (possessive case) was Martis. The corresponding day of the week was therefore named dies martis or martis dies.

In the Vulgar Latin spoken in what was to become France, martis dies evolved various forms such as martedi, martes (c.f. Spanish martes) and the modern French mardi, in which the Latin origin is still easy to see.

The Germanic equivalent of the Roman Mars was Tiw, known to the Norse as Tyr. The name Tiw was probably pronounced much as we today pronounce the Tue of Tuesday.

To the Angles and Saxons, Tiw was the god of war and treaties. He also stood for justice and honour. As befits a warrior, Tiw was considered a master of swordplay. The Germanic name Tiw is related to the Greek Zeus and Tiw, like Zeus was also a sky god.

Unusually among gods, Tiw had only one hand. According to the myths, the gods banded together to bind the monstrous and evil wolf called Fenrir. They tried to do this by deception and the wolf agreed to be bound only if one of the gods placed his hand in the wolf’s mouth as a token of good faith. Tiw, the honourable, proffered his own hand but the wolf bit it off.

For more about Tiw, see the Wikipedia article on Tyr.

In Anglo-Saxon, the genitive of Tiw was Tiwes and his day was called Tiwesdæg which eventually became the modern Tuesday.

Wednesday and mercredi

In our examination of the names of the days in English and French (and incidentally, in Babylonian and Latin), we have reached the middle of the week (Mittwoch in German) with Wednesday.

While most people pronounce Wednesday as two syllables – “wenzday” – a few, perhaps considered “old school” by the majority, pronounce it with three: “wed’nsday”, which, as we shall see, is slightly nearer the original from which it derives. With 9 letters, it is also the longest of the English day names.

Here is a reminder of these names in the 5 languages we are considering:

English Babylonian Anglo-Saxon Latin French
Wednesday Nabû Wodnesdæg dies Mercurii mercredi

The significance of Nabû to the Babylonians is succinctly described in its Encyclopædia Britannica entry as follows:

Nabu, biblical Nebo, major god in the Assyro-Babylonian pantheon. He was patron of the art of writing and a god of vegetation. Nabu’s symbols were the clay tablet and the stylus, the instruments held to be proper to him who inscribed the fates assigned to men by the gods.

The Germanic tribes, among whom were the invaders of Britain who would become known to history as the Anglo-Saxons, named this day after the god Woden.

Woden was also known as Odin, a god with many and somewhat confusing characteristics. He seems to have shared with Tiw the quality of being a warlike god whose protection could be sought in battle. In Norse mythology, Odin presided over Valhalla where he was joined by warriors fallen in battle. His favourite weapon was the spear, with which he was often depicted, and he had only one eye, having given the other in exchange for wisdom. For more details, see the Wikipedia article on Odin.

In the Anglo-Saxon language, the genitive (possessive case) of Woden is Wodnes, giving Wodnesdæg for the name of his day and, ultimately, our modern Wednesday.

The Romans dedicated this day of the week to Mercury or Mercurius in Latin. This god’s Greek equivalent was Hermes, the two of them having many traits in common. Mercury was the god of commerce and communication and as such was the messenger of the gods and the patron of merchants and messengers. He was also known to be a trickster and was the patron of thieves. For more details, see the Wikipedia article Mercury (mythology).

The genitive of Mercurius is Mercurii and so his day was called by the Romans Dies Mercurii or Mercurii dies. As Vulgar Latin evolved into modern Romance languages and their dialects, Mercurii was often mutated into Mercuris by analogy with Martis (genitive of Mars) and Veneris (genitive of Venus). Sometimes the name alone became the day name and thus Mercuris became the Spanish miércoles. The French kept to Mercuris dies which eventually mutated into the modern mercredi.

Thursday and jeudi

Having passed the middle of the week with Wednesday or mercredi, we arrive at Thursday.

Here is a reminder of the names of this day in the five languages under discussion:

English Babylonian Anglo-Saxon Latin French
Thursday Marduk Ðunresdæg dies Iovis jeudi

The Babylonians dedicated this day to the god Marduk. Originally the god of thunder who conquered the monster of primeval chaos, Tiamat , he became the patron god of the city of Babylon. This honourable role enhanced his reputation and he rose in importance until he became the chief of the Babylonian gods. For more details, see the Encyclopædia Britannica’s article Marduk.

To the Romans, the chief of the gods was he who was known variously as Iuppiter or Iovis, names that were transliterated into Engish as Jupiter and Jove. To the Greeks he was Zeus. Originally a sky god, he could be petitioned to produce rain in the midst of drought but he also stood for morality and duty. He presided over war and treaties but his many roles are too numerous to list here. For more details, see the Encyclopædia Britannica’s article Jupiter.

The genitive of Iovis is also Iovis and so his day was called dies Iovis or Iovis dies.

Although it is now customary to spell the Latin word for Jove with a ‘v’, we should remember that that letter (and sound) did not exist in Classical Latin and represents an original ‘u’, although this was often represented as a ‘v’, because this was easier to cut when carving in stone.. The name of this god would have been written IOUIS (or IOVIS) and pronounced something like “yowiss”. The consonantal ‘i’ (pronounced like consonantal ‘y’ in English words like “yes”) became a fricative ‘j’ sound in French and other Romance languages. Simplification of the words in popular speech caused the loss of the ‘s’ sounds and a mutation of the vowel sounds, leading eventually to modern jeudi.

The statement that the English word Thursday derives from the Anglo-Saxon Ðunresdæg might seem counter-intuitive at first glance. The first letter, ‘Ð’, is an upper case version of the letter the Anglo-Saxons called þorn (“thorn”) which was replaced in later English with the letter-pair ‘th’. The day name was therefore pronounced something like “Thunresda(g)”.

Ðunres is the genitive of the name Ðunor, or Thunor, in modern spelling. This god is more familiar to us these days in the Norse version of his name, Ðórr or Thor. He was probably the most important of the old Germanic gods. His name is cognate with words for thunder and he was associated with the forces of nature, including the weather. His favourite weapon was the hammer but this was not used only in fighting: Thunor was also the god of the forge and patron of blacksmiths. It was believed that the thunder was the sound of Thunor hammering on the celestial anvil and the lightning, the sparks given off as he struck the object he was working on. For more details, see the Wikipedia article Thor.

You may be tempted to think that modern Thursday derives from Ðorr (“Thor”) rather than from Ðunor (“Thunor”) but in fact, Ðunresdæg gradually mutated into Ðurresdæg, from which an evolution into “Thursday” can easily be imagined.

Friday and vendredi

Finally, we come to the second of only two days that celebrate feminine, as opposed to masculine, deities. The first was the moon, which is considered feminine in Babylonian, Latin and French but masculine in Anglo-Saxon, while in modern English, it has no gender though is sometimes treated as feminine in poetry. In contrast, the deity we are considering now, is feminine in all five of our languages.

Here is a reminder of the day names in those languages:

English Babylonian Anglo-Saxon Latin French
Friday Ishtar Frigedæg dies Veneris vendredi

The goddess Ishtar enjoyed great popularity among the Babylonians. She was a fertility figure and was alo associated with the planet Venus, making her the goddess of sexual love. She was the patron of prostitutes and the alehouse and her cult may have included ritual prostitution. She was a complex figure, though, and was also associated with death and disaster. For more details, see the Encyclopædia Britannica’s article Ishtar.

The Romans acquired Venus as a gooddess relatively late but she had been worshipped among the Latin peoples from ancient times. Originally a fertility goddess, she became identified by the Romans with the Greek Astarte, the goddess of love, and as the latter was considered the daughter of Zeus, so Venus came to be regarded as the daughter of Jupiter, a fact that enormously increased her importance. She was also renowned as the mother of Cupid. There is a lot more to her than this, however, and for more information, see the Encyclopædia Britannica’s article Venus.

In Latin, as in modern English, this goddess and her planet were called Venus. The Latin genitive (possessive case) is Veneris and so her day was called dies Veneris or Veneris dies.

The Latin Veneris dies formed the basis of the modern French name for that day of the week. As in other cases, such as mercredi and jeudi, the two ‘s’ sounds were lost and so was the unstressed second ‘e’. The resulting putative word *ven’redi is quite hard to pronounce (try it!) without a “virtual” ‘d’ creeping in, especially by attraction with the ‘d’ later in the word. Whatever the reason, the ‘d’ did come in and Veneris dies eventually mutated to vendredi in modern French.

The goddess called Frigg was widely known and worshipped among other Germanic and Norse peoples. The wife of Odin, she was a goddess of the earth and could be petitioned for a good harvest. She was, of course, also the goddess of love, as well as of the home. For more details, see the Wikipedia article Frigg.

The genitive of her name is Frige and so her day was called Frigedæg. Remembering that in Anglo-Saxon, ‘g’ often became a sound like the ‘y’ in “yes”, it is easy to see how Frigedæg could mutate into the modern Friday.