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A fortnight is a unit of time equal to 14 days (2 weeks). The word derives from the Old English term fēowertyne niht, meaning "fourteen nights". [1] [2]


Some wages and salaries are paid on a fortnightly basis; [3] however, in North America it is far more common to use the term biweekly . Neither of these terms should be confused with semimonthly , which divides a year into exactly 24 periods (12 months × 2), instead of the 26 (≈52 weeks ÷ 2) of fortnightly/biweekly. [4]


In astronomy, a lunar fortnight is half a lunar synodic month, equivalent to the mean period between a full moon and a new moon (and vice versa). This is equal to 14.77 days. [5] [6]


A fortnight is a term that is used prominently in sporting circles – as many major sports events have a two-week or approximately half-month time frame. In tennis, Wimbledon and the other Grand Slam tournaments are played over two weeks and are often referred to as lasting a fortnight. The Summer and now even the Winter Olympics are also slightly longer than two weeks in length and may be referenced in this manner as well. Likewise various other events in the sporting world could fall under this characterization.

In other languages

In many languages, there is no single word for a two-week period, and the equivalent terms "two weeks", "14 days", or "15 days" (counting inclusively) have to be used.

See also

Related Research Articles

The English language was first introduced to the Americas by British colonization, beginning in the late 16th and early 17th centuries. The language also spread to numerous other parts of the world as a result of British trade and colonisation and the spread of the former British Empire, which, by 1921, included about 470–570 million people, about a quarter of the world's population. Written forms of British and American English as found in newspapers and textbooks vary little in their essential features, with only occasional noticeable differences.

Lunar calendar Type of calendar

A lunar calendar is a calendar based on the monthly cycles of the Moon's phases, in contrast to solar calendars, whose annual cycles are based only directly on the solar year. The most commonly used calendar, the Gregorian calendar, is a solar calendar system that originally evolved out of a lunar calendar system. A purely lunar calendar is also distinguished from a lunisolar calendar, whose lunar months are brought into alignment with the solar year through some process of intercalation. The details of when months begin varies from calendar to calendar, with some using new, full, or crescent moons and others employing detailed calculations.

Week Time unit equal to seven days

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

Eclipse cycle

Eclipses may occur repeatedly, separated by certain intervals of time: these intervals are called eclipse cycles. The series of eclipses separated by a repeat of one of these intervals is called an eclipse series.

The saros is a period of exactly 223 synodic months, that can be used to predict eclipses of the Sun and Moon. One saros period after an eclipse, the Sun, Earth, and Moon return to approximately the same relative geometry, a near straight line, and a nearly identical eclipse will occur, in what is referred to as an eclipse cycle. A sar is one half of a saros.

A lunar day is the period of time for Earth's Moon to complete one rotation on its axis with respect to the Sun. Due to tidal locking, it is also the time the Moon takes to complete one orbit around Earth and return to the same phase.

The Hindu calendar refers to a set of various lunisolar calendars that are traditionally used in the Indian subcontinent and South-east Asia, with further regional variations for social and Hindu religious purposes. They adopt a similar underlying concept for timekeeping based on sidereal year for solar cycle and adjustment of lunar cycles in every three years, however also differ in their relative emphasis to moon cycle or the sun cycle and the names of months and when they consider the New Year to start. Of the various regional calendars, the most studied and known Hindu calendars are the Shalivahana Shaka found in South India, Vikram Samvat (Bikrami) found in Nepal North and Central regions of India, Tamil calendar used in Tamil Nadu, and the Bengali calendar used in the Bengal – all of which emphasize the lunar cycle. Their new year starts in spring. In contrast, in regions such as Kerala, the solar cycle is emphasized and this is called the Malayalam calendar, their new year starts in autumn, and these have origins in the second half of the 1st millennium CE. A Hindu calendar is sometimes referred to as Panchanga (पञ्चाङ्ग).

The Celtic calendar is a compilation of pre-Christian Celtic systems of timekeeping, including the Gaulish Coligny calendar, used by Celtic countries to define the beginning and length of the day, the week, the month, the seasons, quarter days, and festivals.

The early Germanic calendars were the regional calendars used amongst the early Germanic peoples, prior to the adoption of the Julian calendar in the Early Middle Ages. It was an element of early Germanic culture.

The Tibetan calendar is a lunisolar calendar, that is, the Tibetan year is composed of either 12 or 13 lunar months, each beginning and ending with a new moon. A thirteenth month is added every two or three years, so that an average Tibetan year is equal to the solar year.

Vikram Samvat and also known as the Vikrami calendar, is the historical Hindu calendar in the Indian subcontinent. It is the official calendar of Nepal. In India it is used in several states. The calendar uses lunar months and solar sidereal years.

Coligny calendar Calendar found in Coligny, Ain, France in 1897

The Coligny calendar is a Gaulish peg calendar or parapegma made in Roman Gaul in the 2nd century, giving a five-year cycle of a lunisolar calendar with intercalary months. It is the most important evidence for the reconstruction of an ancient Celtic calendar. It is written in Latin inscriptional capitals and is in the Gaulish language. The restored tablet contains sixteen vertical columns, with 62 months distributed over five years.

Medical terminology is language used to precisely describe the human body including its components, processes, conditions affecting it, and procedures performed upon it. Medical terminology is used in the field of medicine.

Paksha refers to a fortnight or a lunar phase in a month of the Hindu lunar calendar.

Quinzaine is a word of French language derivation: 'a quinzaine' is to Fifteen as 'a dozen' is to Twelve, and 'a trental' is to Thirty. It has various contexts of use in English. 'La quinzaine' is used in French to indicate a two week period, just like 'huit jours' indicates a one week period even though two weeks are fourteen days and one week is 7 days. It is an old habit to add the current day as to say 'in two weeks plus today'. The English language equivalent is 'fortnight' which means fourteen days.

An eclipse season is one of only two periods during each year when eclipses can occur, due to the variation in the orbital inclination of the Moon. Each season lasts about 35 days and repeats just short of six months later, thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. During the eclipse season, the inclination of the Moon's orbit is low, hence the Sun, Moon, and Earth become aligned straight enough for an eclipse to occur.

The Somali calendar is based on both the solar and lunar calendar systems. The calendar was used by farmers and herders to determine the weather and seasons, it helped them in their needs. The Somali solar calendar is known as Amin-tiris or Shin-tiris while the lunar calendar was known as Dayax-tiris.

Eight-day week "Week" in certain historical calendars that consisted of eight days

Some historical calendars had "weeks" consisting of eight days.

Lunar month unit of time

In lunar calendars, a lunar month is the time between two successive syzygies. The precise definition varies, especially for the beginning of the month.

Muisca calendar

The Muisca calendar was a lunisolar calendar used by the Muisca. The calendar was composed of a complex combination of months and three types of years were used; rural years, holy years, and common years. Each month consisted of thirty days and the common year of twenty months, as twenty was the 'perfect' number of the Muisca, representing the total of extremeties; fingers and toes. The rural year usually contained twelve months, but one leap month was added. This month represented a month of rest. The holy year completed the full cycle with 37 months.


  1. "Fortnight". The Concise Oxford Dictionary (5th ed.). 1964. p. 480.
  2. Senight, sennight or se'night (seven-night), an old word for the week, was still in use in the early 19th century, to judge from Jane Austen's letters.
  3. "Australian Government – How much Disability Support Pension do I get?". Archived from the original on 16 April 2008. Retrieved 22 May 2008.
  4. Steven Bragg (22 June 2010). "What is the difference between a semimonthly and biweekly payroll?". AccountingTools. Retrieved 23 November 2015. Semimonthly is paid 24 times per year, and the biweekly is paid 26 times per year.
  5. Littmann, Mark; Fred Espenak; Ken Willcox (2008). Totality: Eclipses of the Sun. Oxford University Press. ISBN   0-19-953209-5.
  6. Weisstein, Eric W. "Synodic Month definition".
  7. BBC (16 October 2014). "BBC Wales - Catchphrase". BBC Wales. Retrieved 18 November 2016. Wythnos is a week.
  8. "Do You Know How to Say Fortnight in Different Languages?".