Names of the days of the week

The names of the days of the seven-day week in many languages are derived from the names of the classical planets in Hellenistic astrology, which were in turn named after contemporary deities, a system introduced in the Roman Empire during Late Antiquity. In some other languages, the days are named for corresponding deities of the regional culture, either beginning with Sunday or with Monday. In the international standard ISO 8601, Monday is treated as the first day of the week.

Days named after planets

Greco-Roman tradition

Between the 1st and 3rd centuries the Roman Empire gradually replaced the eight-day Roman nundinal cycle with the seven-day week. Our earliest evidence for this new system is a Pompeiian graffito referring to the 6th February (viii idus Februarius) of the year AD 60 as dies solis ("Sunday"). Another early witness is a reference to a lost treatise by Plutarch, written in about AD 100, which addressed the question of Why are the days named after the planets reckoned in a different order from the actual order?.

Workweek and weekend

The workweek and weekend are those complementary parts of the week devoted to labour and rest, respectively. The legal working week (British English), or workweek (U.S. English), is the part of the seven-day week devoted to labour. In most of the Western world it is Monday to Friday; the weekend is a time period including Saturday and Sunday. A weekday is any day of the working week. As well as places of work, other institutions often follow the same days, such as places of education.

Some people extend the weekend to Friday nights as well. In some Christian traditions, Sunday is the "Lord's Day" and the day of rest and worship. Jewish Shabbat or Biblical Sabbath lasts from sunset on Friday to the fall of full darkness on Saturday, leading to a Friday–Saturday weekend in Israel. Some Muslim-majority countries historically had a Thursday–Friday or Friday–Saturday weekend; however, recently many such countries have shifted from Thursday–Friday to Friday–Saturday, or to Saturday–Sunday. The French Revolutionary Calendar had ten-day weeks (called décades) and allowed décadi, one out of the ten days, as a leisure day.

Seven Days

Seven Days or 7 Days may refer to:

Film

Television

Newspapers

Music

Songs

Day

A day is a unit of time. In common usage, it is an interval equal to 24 hours. It also can mean the consecutive period of time during which the Sun is above the horizon, also known as daytime. The period of time during which the Earth completes one rotation with respect to the Sun is called a solar day.

Several definitions of this universal human concept are used according to context, need and convenience. In 1967, the second was redefined in terms of the wavelength of light, and was designated the SI base unit of time. The unit of measurement "day", redefined in 1967 as 86 400 SI seconds and symbolized d, is not an SI unit, but is accepted for use with SI. A civil day is usually also 86 400 seconds, plus or minus a possible leap second in Coordinated Universal Time (UTC), and, in some locations, occasionally plus or minus an hour when changing from or to daylight saving time. The word day may also refer to a day of the week or to a calendar date, as in answer to the question "On which day?" The life patterns of humans and many other species are related to Earth's solar day and the day-night cycle (see circadian rhythms).

Week

A week is a time unit equal to seven days. It is the standard time period used for cycles of work days and rest days in most parts of the world, mostly alongside (but not strictly part of) the Gregorian calendar.

The days of the week were named in different languages after classical planets, various deities (example: Thursday – Thor's day, a variation after Jupiter's day from Roman times) and heavenly bodies (example: Sunday – Sun's day) and other sources. In English, the names are Monday, Tuesday, Wednesday, Thursday, Friday, Saturday and Sunday.

ISO 8601 includes the ISO week date system, a numbering system for weeks within a given year – each week begins on a Monday and is associated with the year that contains that week's Thursday (so that if a year starts in a long weekend Friday–Sunday, week number one of the year will start after that).

The term "week" is sometimes expanded to refer to other time units comprising a few days, such as the nundinal cycle of the ancient Roman calendar.