Week
A seven-day unit of time used globally for calendars and scheduling.
A week is a unit of time equal to seven days, serving as the standard calendrical period between a day and a month in most parts of the world. There are just over 52 weeks in a year. The days of the week are commonly used to designate work days, rest days, and holy days. The term "week" can also refer to sub-sections like the workweek and weekend, and certain weeks may be designated for a particular purpose, such as Golden Week in China and Japan, or awareness weeks like National Family Week in Canada.
Historically, week lengths varied across cultures. Ancient Egypt used a ten-day week, the Etruscans and early Romans an eight-day week, and some modern West African cultures have four- or five-day market weeks. The Romans later adopted a seven-day week, originally an astrological cycle naming each day after a classical planet and its associated god. As Christianity spread, this astrological week merged with the Christian seven-day week centered on Sunday. In the fourth century AD, the first day was identified with the sun (Sol Invictus), a Mithraic god, and under Emperor Constantine this arrangement was Christianized. In AD 321, Constantine decreed a seven-day week in the Roman Empire, making Sunday a public holiday, a practice that spread across Europe and then the world.
The English names for the days derive from Germanic equivalents of the Roman names, except for Saturday, which retains the Roman Saturn. Which day is considered first varies by culture, though Saturday, Sunday, or Monday are the most common. The three Abrahamic religions observe different holy days: Christians on Sunday, Muslims on Friday, and Jews on Saturday (Shabbat). The word "week" comes from a Common Germanic root meaning "turn, move, change." A week is defined as exactly seven days: 168 hours, 10,080 minutes, or 604,800 seconds. In the Gregorian calendar, a year has 52 weeks plus one day (or two in a leap year).
- weeks_per_year
- 52 weeks + 1 day (2 days in a leap year)
- first_day_variation
- Saturday, Sunday, or Monday, depending on culture
- ISO_standard_first_day
- Monday
- holy_days
- Sunday (Christianity), Friday (Islam), Saturday (Judaism)
Lore & Background
The Babylonians celebrated the 7th, 14th, 21st, and 28th days of the lunar month as holy days. The Romans initially used an eight-day week but later adopted a seven-day astrological week, naming each day after a classical planet and its associated god. This system merged with the Christian seven-day week, which itself originated from the Jewish week centered on Saturday. The English names for the days derive from Germanic equivalents of the Roman names, except Saturday, which retained its Latin name. The ordering of weekday names follows a planetary hours system, not the classical order of the planets. Cultures vary on which day is considered first: most of Europe, China, and Oceania count Monday as first; much of America and southern Africa count Sunday; and many Arabic- and Persian-speaking countries use Saturday. The International Organization for Standardization uses Monday as the first day in its ISO week date system.
Reader's Guide
The week is a fundamental unit of time that structures social, religious, and economic life across the globe. Its seven-day cycle, though not based on any natural astronomical period, has become nearly universal due to the influence of the Roman Empire and the spread of Christianity. The week's significance extends beyond mere timekeeping: it organizes workweeks and weekends, designates holy days for the three Abrahamic religions, and provides a framework for awareness campaigns and cultural celebrations like Golden Week. The historical adoption of the seven-day week by Constantine the Great cemented its place in Western civilization, and its subsequent global spread made it the standard. Its persistence across cultures and millennia demonstrates its deep integration into human society.
Did You Know?
- The English word 'week' comes from Old English 'wice', ultimately from a Common Germanic root meaning 'turn, move, change'.
- The Romans originally used an eight-day week before switching to a seven-day astrological week.
- The seven-day week is named in many languages by a word derived from 'seven', such as 'hebdomad' from Greek.
Frequently Asked Questions
What are Week's powers and role?
Week structures the rhythm of daily life by carving out work days, rest days, and holy days within its seven-day span. It accommodates multiple faiths simultaneously, with Sunday set aside for Christianity, Friday for Islam, and Saturday for Judaism.
How does Week's story end?
Each Week simply closes after its seventh day and the next one begins immediately, so there is no true finale. In a standard calendar year, 52 complete Weeks finish with one extra day left over, or two in a leap year.
Why is Week important?
Week gives billions of people a shared scheduling backbone for coordinating labor, worship, and rest across cultures and continents. Without that common seven-day frame, aligning workweeks, school terms, and religious observances globally would be far more chaotic.
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