Undecimber

Last updated

Undecimber or Undecember is a name for the 13th month in a calendar that normally has 12 months.

Contents

Etymology

The word undecimber is based on the Latin word undecim meaning "eleven". It is formed in analogy with December, which, though the twelfth month in the Gregorian calendar, derives from decem meaning "ten". The word undecember (abbreviated Vnde) is recorded from a Roman inscription according to the Oxford Latin Dictionary, which defines it as "a humorous name given to the month following December". [1]

Some recent authors report the names "Undecember" and "Duodecember" for the two intercalary months inserted between November and December upon the adoption of the Julian calendar in 44 BCE, including the World Calendar Association [2] and Isaac Asimov. [3] This claim has no contemporary evidence; Cicero refers to the months as "intercalates prior and intercalates posterior" in his letters. [4]

Historian Cassius Dio tells that Licinus, procurator of Gaul, added two months to the year 15 BCE, because taxes were paid by the month. [5] Though not named by Dio, who wrote in Greek, August Immanuel Bekker suggested these might have been called "Undecember" and "Duodecember".[ citation needed ]

Computing

In the Java Platform, Standard Edition, the java.util.Calendar class includes support for calendars which permit thirteen months. [6] Although the Gregorian calendar used in most parts of the world includes only twelve months, there exist some lunar calendars that are divided into synodic months, with an intercalary or "leap" month added in some years. For example, in the Hebrew calendar seven years out of every nineteen (37%) have the "embolismic month" Adar I. [6] [7] The constant java.util.Calendar.UNDECIMBER represents such a month. [8]

Accounting (called "Month 13")

In accounting, a thirteenth month is sometimes used to adjust financial statements for an entire year without affecting monthly results. For example, an organization may wish to adjust its books to reflect the fact that some of its sales and resulting payments due from customers will not be paid. If an organization only does this once per year the organization can attribute these adjustments to "Month 13" so as not to inaccurately post a full year's worth of write offs to one month. [9]

Further months

Similar names exist for additional months in calendars extended beyond 13 months. For instance, duodecember is a 14th month, and tridecember is a 15th month.[ citation needed ]

See also

Related Research Articles

<span class="mw-page-title-main">Chinese calendar</span> Lunisolar calendar from China

The traditional Chinese calendar is a lunisolar calendar, combining the solar, lunar, and other cycles for various social and religious purposes. More recently, in China and Chinese communities the Gregorian calendar has been adopted and adapted in various ways, and is generally the basis for standard civic purposes, but incorporating traditional lunisolar holidays. However, there are many types and subtypes of the Chinese calendar, partly reflecting developments in astronomical observation and horology, with over a millennium plus history. The major modern form is the Gregorian calendar-based official version of the Mainland China, although diaspora versions are also notable in other parts of China and Chinese-influenced cultures; however, aspects of the traditional lunisolar calendar remain popular, including the association of the twelve animals of the Chinese Zodiac in relation to months and years.

<span class="mw-page-title-main">Hebrew calendar</span> Lunisolar calendar used for Jewish religious observances

The Hebrew calendar, also called the Jewish calendar, is a lunisolar calendar used today for Jewish religious observance and as an official calendar of Israel. It determines the dates of Jewish holidays and other rituals, such as yahrzeits and the schedule of public Torah readings. In Israel, it is used for religious purposes, provides a time frame for agriculture, and is an official calendar for civil holidays alongside the Gregorian calendar.

Intercalation or embolism in timekeeping is the insertion of a leap day, week, or month into some calendar years to make the calendar follow the seasons or moon phases. Lunisolar calendars may require intercalations of days or months.

The Julian calendar is a solar calendar of 365 days in every year with an additional leap day every fourth year. The Julian calendar is still used as a religious calendar in parts of the Eastern Orthodox Church and in parts of Oriental Orthodoxy as well as by the Amazigh people.

A leap year is a calendar year that contains an additional day compared to a common year. The 366th day is added to keep the calendar year synchronised with the astronomical year or seasonal year. Since astronomical events and seasons do not repeat in a whole number of days, calendars having a constant number of days each year will unavoidably drift over time with respect to the event that the year is supposed to track, such as seasons. By inserting ("intercalating") an additional day—a leap day—or month—a leap month—into some years, the drift between a civilization's dating system and the physical properties of the Solar System can be corrected.

<span class="mw-page-title-main">Lunisolar calendar</span> Calendar with lunar month, solar year

A lunisolar calendar is a calendar in many cultures, incorporating lunar calendars and solar calendars. The date of lunisolar calendars therefore indicates both the Moon phase and the time of the solar year, that is the position of the Sun in the Earth's sky. If the sidereal year is used instead of the solar year, then the calendar will predict the constellation near which the full moon may occur. As with all calendars which divide the year into months there is an additional requirement that the year have a whole number of months. In some case ordinary years consist of twelve months but every second or third year is an embolismic year, which adds a thirteenth intercalary, embolismic, or leap month.

A month is a unit of time, used with calendars, that is approximately as long as a natural orbital period of the Moon; the words month and Moon are cognates. The traditional concept of months arose with the cycle of Moon phases; such lunar months ("lunations") are synodic months and last approximately 29.53 days, making for roughly 12.37 such months in one Earth year. From excavated tally sticks, researchers have deduced that people counted days in relation to the Moon's phases as early as the Paleolithic age. Synodic months, based on the Moon's orbital period with respect to the Earth–Sun line, are still the basis of many calendars today and are used to divide the year.

<span class="mw-page-title-main">Roman calendar</span> Calendar used by the Roman Kingdom and Roman Republic

The Roman calendar was the calendar used by the Roman Kingdom and Roman Republic. Although the term is primarily used for Rome's pre-Julian calendars, it is often used inclusively of the Julian calendar established by the reforms of the Dictator Julius Caesar and Emperor Augustus in the late 1st century BC.

<span class="mw-page-title-main">Adar</span> 12th month of the Hebrew calendar

Adar is the sixth month of the civil year and the twelfth month of the religious year on the Hebrew calendar, roughly corresponding to the month of March in the Gregorian calendar. It is a month of 29 days.

<span class="mw-page-title-main">Zoroastrian calendar</span> Religious date system

Adherents of Zoroastrianism use three distinct versions of traditional calendars for liturgical purposes, all derived from medieval Iranian calendars and ultimately based on the Babylonian calendar as used in the Achaemenid empire. Qadimi ("ancient") is a traditional reckoning introduced in 1006. Shahanshahi ("imperial") is a calendar reconstructed from the 10th century text Denkard.

The Baháʼí calendar used in the Baháʼí Faith is a solar calendar consisting of nineteen months and four or five intercalary days, with new year at the moment of Northern spring equinox. Each month is named after a virtue, as are the days of the week. The first year is dated from 1844 CE, the year in which the Báb began teaching.

<span class="mw-page-title-main">Babylonian calendar</span> Lunisolar calendar

The Babylonian calendar was a lunisolar calendar used in Mesopotamia from around the second millennium BCE until the Seleucid Era, and it was specifically used in Babylon from the Old Babylonian Period until the Seleucid Era. The civil lunisolar calendar was used contemporaneously with an administrative calendar of 360 days, with the latter used only in fiscal or astronomical contexts. The lunisolar calendar descends from an older Sumerian calendar used in the 4th and 3rd millennia BCE.

Various ancient Greek calendars began in most states of ancient Greece between autumn and winter except for the Attic calendar, which began in summer.

Mercedonius, also known as Mercedinus, Interkalaris or Intercalaris, was the intercalary month of the Roman calendar. The resulting leap year was either 377 or 378 days long. It theoretically occurred every two years, but was sometimes avoided or employed by the Roman pontiffs for political reasons regardless of the state of the solar year. Mercedonius was eliminated by Julius Caesar when he introduced the Julian calendar in 45 BC.

The Buddhist calendar is a set of lunisolar calendars primarily used in Tibet, Cambodia, Laos, Myanmar, Bangladesh, India, Sri Lanka, Thailand and Vietnam as well as in Malaysia and Singapore and by Chinese populations for religious or official occasions. While the calendars share a common lineage, they also have minor but important variations such as intercalation schedules, month names and numbering, use of cycles, etc. In Thailand, the name Buddhist Era is a year numbering system shared by the traditional Thai lunar calendar and by the Thai solar calendar.

The intercalary month or epagomenal days of the ancient Egyptian, Coptic, and Ethiopian calendars are a period of five days in common years and six days in leap years in addition to those calendars' 12 standard months, sometimes reckoned as their thirteenth month. They originated as a periodic measure to ensure that the heliacal rising of Sirius would occur in the 12th month of the Egyptian lunar calendar but became a regular feature of the civil calendar and its descendants. Coptic and Ethiopian leap days occur in the year preceding Julian and Gregorian leap years.

The Ancient Macedonian calendar is a lunisolar calendar that was in use in ancient Macedon in the 1st millennium BCE. It consisted of 12 synodic lunar months, which needed intercalary months to stay in step with the seasons. By the time the calendar was being used across the Hellenistic world, seven total embolimoi were being added in each 19 year Metonic cycle. The names of the ancient Macedonian Calendar remained in use in Syria even into the Christian era.

<span class="mw-page-title-main">Zoroastrian festivals</span>

Zoroastrianism has numerous festivals and holy days, all of which are bound to the Zoroastrian calendar. The Shahenshahi and Kadmi variants of the calendar do not intercalate leap years and hence the day of the Gregorian calendar year on which these days are celebrated shifts ahead with time. The third variant of the Zoroastrian calendar, known as either Fasli or Bastani, intercalates according to Gregorian calendar rules and thus remains synchronous with the seasons. For details on the differences, see Zoroastrian calendar.

The Burmese calendar is a lunisolar calendar in which the months are based on lunar months and years are based on sidereal years. The calendar is largely based on an older version of the Hindu calendar, though unlike the Indian systems, it employs a version of the Metonic cycle. The calendar therefore has to reconcile the sidereal years of the Hindu calendar with the Metonic cycle's near tropical years by adding intercalary months and days at irregular intervals.

The Gregorian calendar is the calendar used in most parts of the world. It went into effect in October 1582 following the papal bull Inter gravissimas issued by Pope Gregory XIII, which introduced it as a modification of, and replacement for, the Julian calendar. The principal change was to space leap years differently so as to make the average calendar year 365.2425 days long, more closely approximating the 365.2422-day 'tropical' or 'solar' year that is determined by the Earth's revolution around the Sun.

References

  1. Glare, P.G. (2002). Oxford Latin Dictionary. Clarendon Press. ISBN   0-19-864224-5.
  2. Jézéquel, Jules (1937). "Why the World Needs This Reform". Journal of Calendar Reform. 7. New York City: World Calendar Association: 64.
  3. Asimov, Isaac; John Bradford (1963). The clock we live on (revised ed.). Collier Books. p. 118. ISBN   0-200-71100-8.
  4. Heiland, W.E. (1909). "Chap LVIII: From the Battle of Thapsus to the death of Caesar: -46 - -44". The Roman Republic. Vol. 3. Cambridge: Cambridge University Press. pp. 347 §1269. ISBN   0-89005-577-7.
  5. Cassius Dio (1914–1927). "LIV 21.5". Roman History. Loeb Classical Library. Translated by Earnest Cary. Harvard University Press. p. 335. ISBN   0-665-72855-7.
  6. 1 2 Janert, Philipp K. (2007-06-04). "Making Sense of Java's Dates". On Java. O'Reilly Media . Retrieved 2007-12-13.
  7. "In a leap year, is the extra month Adar I or Adar II?". Mi Yodeya StackExchange.
  8. "java.util Class Calendar: UNDECIMBER". Java Platform, Standard Edition 6: API Specification. Sun Microsystems. 2008. Retrieved 2009-05-22.
  9. L. Evans, Denise L.; Evans, William (2023). The Complete Real Estate Encyclopedia. The McGraw-Hill Companies, Inc. Retrieved 7 Aug 2023.