Names of the days of the week


In a vast number of languages, the names given to the seven days of the week are derived from the names of the seven heavenly bodies which were in turn named after contemporary Hellenistic deities. This system was introduced by the Babylonians and later adopted by the Sumerians. The Roman Empire adopted the system during late antiquity. In some other languages, the days are named after corresponding deities of the regional culture. The seven-day week was adopted in early Christianity from the Hebrew calendar, and gradually replaced the Roman internundinum. Eight-day and seven-day weeks existed side-by-side until Emperor Constantine made the seven-day week official in AD 321; thereafter, the seven-day week spread throughout the Roman Empire and eventually through Christian cultures around the world.
The history of the seven-day week can be traced to ancient civilizations. Sunday remained the first day of the week, being considered the day of the sun god Sol Invictus and the Lord's Day, while the Jewish Sabbath remained the seventh. Most historians agree the seven-day week dates back to Babylonians who started using it about 4,000 years ago. The number 7 was sacred to the Babylonians. Emperor Constantine of the Roman Empire made the Day of the Sun a legal holiday centuries later.
In the international standard ISO 8601, Monday is treated as the first day of the week, but in many countries it is counted as the second day of the week.

Days named after planets

Greco-Roman tradition

Between the first and third centuries CE, the Roman Empire gradually replaced the eight-day Roman nundinal cycle with the seven-day week. The earliest evidence for this new system is a Pompeiian graffito referring to 6 February of the year 60 CE as dies solis. Another early witness is a reference to a lost treatise by Plutarch, written in about 100 CE, which addressed the question of: "Why are the days named after the planets reckoned in a different order from the 'actual' order?" The treatise is lost, but the answer to the question is known; see planetary hours.
The Ptolemaic system of planetary spheres asserts that the order of the heavenly bodies from the farthest to the closest to the Earth is Saturn, Jupiter, Mars, Sun, Venus, Mercury, and the Moon; objectively, the planets are ordered from slowest to fastest moving as they appear in the night sky.
The days were named after the classical planets of Hellenistic astrology, in the order: Sun, Moon, Mars, Mercury, Jupiter, Venus, and Saturn.
The seven-day week spread throughout the Roman Empire in late antiquity.
By the fourth century CE, it was in wide use throughout the Empire.
The Greek and Latin names are as follows:
DaySunday
Sun		Monday
Moon		Tuesday
Mars		Wednesday
Mercury		Thursday
Jupiter		Friday
Venus		Saturday
Saturn
Greek
Latin

Romance languages

Except for in Portuguese and Mirandese, the Romance languages preserved the Latin names, except for the names of Sunday, which was replaced by Dominicus , that is, "the Lord's Day", and of Saturday, which was named for the Jewish Sabbath. Mirandese and Portuguese use numbered weekdays, but retain sábado and demingo/''domingo for weekends. Meanwhile, Galician occasionally uses them alongside the traditional Latin-derived names, albeit to a lesser extent.
Day
''		Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Aragonese
Aranese Occitandimengedelunsdimarsdimèrclesdijausdiuendresdissabte
Asturiandomingullunesmartesmiércolesxuevesvienressábadu
Catalandiumengedillunsdimartsdimecresdijousdivendresdissabte
Corsicandumenicalunimartighjovivennari
Frenchdimanchelundimardimercredijeudivendredisamedi
Friuliandomenielunismartarsjoibevinars
Galiciandomingosábado
Italiandomenicalunedìmartedìmercoledìgiovedìvenerdìsabato
Ladin
Ladin sabeda
Liguriandoménegalunedìmartedìmèrcoledìzéuggiavenerdìsàbbo
Lombard duminicalunedémartedémercoldégioedévenerdésabot
Lombard domenegalunedìmartedìmercoldìgiovedìvenerdìsabet
Neapolitanlunnerìmarterìmiercurìgioverìviernarìsàbbatu
Occitandimengedilunsdimarsdimècresdijòusdivendresdissabte
Portuguesedomingosegunda-feiraterça-feiraquarta-feiraquinta-feirasexta-feirasábado
Romanianlunimarțimiercurijoivinerisâmbătă
Romansh dumengialündeschdimardimarculdigövgiavenderdisanda
Romansh dumengiaglindesdimardimesemnagievgiavenderdisonda
Romansh dumengiaglindasdemardemesemdagievgiavendardesonda
Romansh dumengiagliendisdismardismesjamnagievgiavenderdissonda
Romansh dumeingiagliendasgismargismeaseandagievgiavendergissonda
Romansh dumengialündeschdimardimarcurdigövgiavenderdisonda
Sardinian etc.lunis etc. etc. etc. etc.
Sicilian
Spanishdomingolunesmartesmiércolesjuevesviernessábado
Venetiandomenegalunimartimèrcoreziobasabo

Celtic languages

Early Old Irish adopted the names from Latin, but introduced separate terms of Norse origin for Wednesday, Thursday and Friday, then later supplanted these with terms relating to church fasting practices.
Day
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
IrishDomhnachLuanMáirtCéadaoinDéardaoinAoineSatharn
ManxJecrean
Old Irishdiu lunadiu martdiu iathdiu eathamondiu triachdiu saturn
Old Irish
Scottish GaelicDiluainDimàirtDiciadainDiardaoinDihaoineDisathairne

In Welsh, the word for ‘day’ dydd is replaced by the words for ‘morning' bore, ’night’ nos or ‘afternoon’ prynhawn, etc to say ‘Monday morning’ bore Llun, or ‘Friday night’ nos Wener, etc. It is never *nos dydd Llun or *bore dydd Llun which are ungrammatical.
DaySunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Breton
Cornishdy'Suldy'Lundy'Meurthdy'Mergherdy'Yowdy'Gwenerdy'Sadorn
Welshdydd Suldydd Llundydd Mawrthdydd Mercherdydd Iaudydd Gwenerdydd Sadwrn

Albanian language

adopted the Latin terms for Tuesday, Wednesday and Saturday, translated the Latin terms for Sunday and Monday using the native names of Diell and Hënë, respectively, and replaced the Latin terms for Thursday and Friday with the equivalent native deity names Enji and Prende, respectively.
DaySunday
Dielli 		Monday
Hëna 		Tuesday
Wednesday
Thursday
Enji 		Friday
Prende		Saturday
Albaniane diele hënëe martëe mërkurëe enjtee premtee shtunë