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Week

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A week is a unit of time consisting of exactly seven days. It serves as a standard calendrical period between a single day and a full month. In the Western and international context, the week is a vital tool for organizing human life. It helps societies set work days, rest days, and holy days. People often divide the week into sub-sections, such as the workweek or the weekend. Some specific weeks are even designated for special purposes, like Golden Week in China and Japan.

First Day of Week World Map
First Day of Week World Map

Mathematically, a week is a very precise measurement. One week contains exactly 168 hours. This breaks down to 10,080 minutes or 604,800 seconds. When looking at the Gregorian calendar, a standard year contains 52 weeks and one extra day. In a leap year, there are 52 weeks and two extra days. On average, a week represents about 22.9984% of a Gregorian month. It also relates to the Moon, making up about 23.659% of an average lunation.

CLM 14456 71r detail
CLM 14456 71r detail

Different cultures have used various week lengths throughout history. Ancient Egypt utilized ten-day weeks. The Etruscans and early Romans used eight-day weeks. In modern West Africa, some groups use four- or five-day weeks between market days. The seven-day cycle may have roots in the Babylonian calendar. The Babylonians celebrated holy days on the 7th, 14th, 21st, and 28th of a lunar month. They also recognized the 19th day as a significant date. These ancient cycles provided a foundation for how we track time today.

The seven-day week we use now has a complex history. It began as an astrological or planetary week. In this system, each day was named after a classical planet and its corresponding god. The Romans later transitioned to this seven-day model. In AD 321, Emperor Constantine the Great officially decreed the seven-day week in the Roman Empire. He also made Sunday a public holiday. This system eventually merged with the Jewish seven-day week, which centers on the Sabbath. This merger helped spread the seven-day structure across Europe and the rest of the world.

Weekday heptagram
Weekday heptagram

The names of the days in English reflect this planetary history. Most English names are Germanic equivalents of Roman names. Monday is named for the Moon, or Luna. Tuesday comes from Tiw's day, representing the planet Mars. Wednesday is Woden's day, linked to Mercury. Thursday is Thor's day, representing Jupiter. Friday is Friga's day, linked to Venus. Saturday is named after the planet Saturn. Finally, Sunday is named for the Sun, or Sol.

Italian - Bracelet - Walters 41269
Italian - Bracelet - Walters 41269

Religious traditions play a major role in how the week is observed. The three Abrahamic religions each have a specific holy day. Jews observe the Sabbath, or Shabbat, on Saturday. This begins at sunset on Friday and ends at sunset on Saturday. This honors God's rest after the six days of creation. Most Christians observe Sunday as the Lord's Day to honor the resurrection of Jesus. Muslims observe Friday as a sacred day of congregational worship. These different traditions show how the same seven-day cycle can hold different meanings for different people.

First Day of Week World Map
First Day of Week World Map

Cultures also disagree on which day starts the week. The International Organization for Standardization uses Monday as the first day. Most of Europe, China, and Oceania also count Monday as the start. However, much of the Americas, South Asia, and southern Africa count Sunday as the first day. In many Arabic- and Persian-speaking countries, Saturday is the first day. These variations show that while the seven-day length is nearly universal, the way we organize it can change based on where we live.

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🖼️ Images & Media (4)
File:First Day of Week World Map.svg
First Day of Week World Map.svg
File:Italian - Bracelet - Walters 41269.jpg
Italian - Bracelet - Walters 41269.jpg
File:Weekday heptagram.svg
Weekday heptagram.svg
File:CLM 14456 71r detail.jpg
CLM 14456 71r detail.jpg
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