03/03/2022
Interesting Fact: The origin behind Spanish weekday names.
The historical origin or etymology of the days of the week can be linked to Roman mythology. The Romans saw a connection between their gods and the changing face of the nighttime sky, so it became natural to use their gods' names for the planets. The planets the ancient people were able to track in the sky were Mercury, Venus, Mars, Jupiter, and Saturn. Those five planets plus the moon and sun made up the seven major astronomical bodies. When the concept of the seven-day week was imported from Mesopotamian culture early in the fourth century, the Romans used those astronomical names for the days of the week.
The first day of the week was named after the sun, followed by the moon, Mars, Mercury, Jupiter, Venus, and Saturn. The names of the week were adopted with little change throughout most of the Roman Empire and beyond. In only a few cases were changes made.
In Spanish, the five weekdays all retained their planetary names. Those are the five days whose names end in -es, a shortening of the Latin word for "day," dies. Lunes comes from the word for "moon," luna in Spanish, and the planetary connection with Mars is also apparent with martes. The same is true with Mercury/miércoles, and Venus is viernes, meaning "Friday."
The connection with Jupiter is not quite so apparent with jueves unless you know Roman mythology and recall that "Jove" is another name for Jupiter in Latin.
The days for the weekend, Saturday and Sunday, were not adopted using the Roman naming pattern. Domingo comes from a Latin word meaning "Lord's day." And sábado comes from the Hebrew word "sabbath," meaning a day of rest. In Jewish and Christian tradition, God rested on the seventh day of creation.