The names of the seven days of the week that are universally followed, are based on either planetary or numerical classification. There is a slight variation observed in these names, as they are influenced by both religious and secular societies. In such cultures, Sunday is often referred to as the Lord's day. Saturday is believed to be the "day of cleansing" or the "Sabbath". The Planetary names for the days are based on the celestial bodies observed in Earth's sky, like the Sun, the Moon, and planets like Mars, Mercury, Jupiter, Venus, and Saturn. Interestingly, this system corresponds with the names of popular Roman gods who influenced the earlier nomenclature.
In the Germanic and English cultures, the Nordic gods with similar characteristics as their Roman counterparts were substituted, even though there was little or no connection at all with any kind of association with the planets. The English names that are commonly referred by us are derived from the pantheon of Anglo-Saxon deities. While Thursday is named after the Scandinavian deity called Thor, Friday is a revision of the deity called Freyja. However, even within this culture, and in fact in cultures all across the world, Saturday gets its name from Saturn, a Roman deity.
The weekends - Saturday and Sunday are universally accepted as "days of rest". In Israel, the Sabbath lasts from Friday's sunset to Saturday's sunset. Interestingly, in Iran, the weekend is just one day long, with the Friday being the lucky day, and Saturday as the beginning of the week. The name Sunday represents the "Day of the Sun", and it has originated from the pagan/sun-based cultures, during the medieval and pre-medieval times. Monday basically means the "Day of the Moon". This name is based on translations from Latin, French, and Spanish.
The name awarded to the second day of the week called Tuesday, is literally derived from the Old English "Tyr's day", or the heroic God of Combat in Germanic paganism. This name also corresponds to the Latin "Day or Mars". Wednesday is dedicated to the Germanic God Woden, who is considered to be the highest in Norse mythology. He is also a very important god of the Anglo-Saxons. This Latin "Day of Mercury" corresponds with the French "Mercredi". Mercury and Odin were both psychopomps or "soul leaders". They are also associated with poetry and music. Thursday is derived from the Old English "day of Þunor", or from the Modern English name of Thor, who is the Germanic God of Thunder. This "Day of Jupiter" is dedicated to the Chief God of the Roman pantheon, who maintained his power on the basis of his unique thunderbolt.
Friday is named after the Germanic goddess of beauty. She is believed to be an incarnation of the Norse goddess called "Frigg". This day corresponds to Venus, the Roman goddess of beauty, love, and sexual desire, and hence it is also called "Day of Venus". Saturday is named after the Roman god Saturn. The "Day of Saturn" is also the "Day of the Sabbath". Except this deity, the other Gods after whom the days of the week are named, do not preside over the involved planets. Different authorities have various opinions, regarding the above discussed nomenclature.
The seven-day week is now extensively used to handle complex and busy global businesses, and media schedule. The Book of Genesis of the Bible declares how God created the world in six days, and rested on the seventh one called the Sabbath or Saturday. The above concept is not a recent one in human history; in fact it was followed in pre-Christian Babylon and Persia, and in several other cultures.