Have you ever noticed that the words Monday and Lunedì don’t look that dissimilar after all? If you are Italian, you already know
that dì is an old-fashioned way of saying “giorno”, that is day, and you may have also realised that in both words we have a reference to the Moon (LUNedì – MONday). But how is it possible if English and Italian are so different?
The days of the week in Italian derive from Latin and were named after Roman deities. The Romans in turn derived them from a very ancient system first adopted by Babilonian astrologists. Those scientists believed that the first hour of each day of the week was governed by the Sun and other planets.
English derives from the languages spoken by the Germanic tribes who moved to the British Isles back in the 5th century. The Germanic peoples had adapted the Roman system introducing their own gods over the Latin ones. The whole process probably dates back to between 200 and 600 AD, that is before the introduction of Christianity and the collapse of the Western Roman Empire.
Lunedì – Monday
Martedì – Tuesday
Mercoledì – Wednesday
“The day of Mercury” becomes in English “the day of Wodan”, better known as Odin. Odin shared with Mercury a psychopomp feature, i.e. they were both considered a guide of souls after death. In other Germanic languages, the connection with the deity is lost and the name of the day simply means “mid-week”.
Giovedì – Thursday
Venerdì – Friday
Sabato – Saturday
In this case Italian and English followed different routes. The name of this day was originally in honor of Saturn. Later on, due to Christianisation, the Hebrew word “Shabbat” substituted the pagan name, but retained its etymology in English.
Domenica – Sunday
The name comes
 This process is called interpretatio germanica.
 French: lundì, Spanish: lunes
 Old English: monandaeg; German: Montag, Dutch: maandag.
 Latin: Martis dies, French: mardi, Spanish: martes
 Danish: tirstag, Swedish: tisdag
 Latin: : Mercurii dies, French: mercredi, Spanish: miércoles
 Old English: Wōdnesdæg, Dutch: woensdag
 German: Mittwoch, Icelandic Miðviku
 Latin: jovis dies, French: jeudi, Spanish: jueves
 Old English: Þūnresdæg, Dutch: donderdag, German: Donnerstag
 Latin: veneris dies, French: vendredi, Spanish: viernes
 Old English: Frīgedæg, German: Freitag, Dutch: vrijdag
 Latin: Saturni dies
 French: samedi, Spanish: sábádo
 French: dimanche; Spanish: domingo
 Old English: Sunnandæg, German: Sonntag; Dutch: zondag