Twelvemonth & Year

Twelvemonth (pronounced twelve-month)

Twelve months (one year).

Pre 1050: From the Middle English twelmonth, twelfmonthe, twelfmonþe or twelv′munth, from the Old English twelfmōnþ or twelfmōnaþ.  The construct was twelve +‎ month. Twelve was from the Middle English twelve, from the Old English twelf (twelve), from the Proto-Germanic twalif, an old compound of twa- (two) + -lif (left over (in the sense of the two left over after having already counted to ten)) from the primitive Indo-European leyp- (leave, remain). It was cognate with the Saterland Frisian tweelf, tweelif & tweelich (twelve), the West Frisian tolve (twelve), the Dutch twaalf (twelve), the German & Low German twalf & twalv (twelve), the German zwölf (twelve), the Danish, Swedish and Norwegian tolv (twelve) and the Icelandic tólf (twelve).  Month was from the Middle English month & moneth, from the Old English mōnaþ (month), from the Proto-Germanic mēnōþs (month), from the primitive Indo-European mḗhins (moon, month), probably from meh- (to measure), a reference to the moon's phases as the measure of time, the construct understood as moon +‎ -th.  It was cognate with the Scots moneth (month), the North Frisian muunt (month), the Saterland Frisian mound (month), the Dutch maand (month), the Low German Maand & Monat (month), the German Monat (month), the Danish and Norwegian Bokmål måned (month), the Norwegian Nynorsk & Swedish månad (month), the Icelandic mánuði (month), the Latin mēnsis (month), the Ancient Greek μήν (mḗn), the Armenian ամիս (amis), the Old Irish mí and the Old Church Slavonic мѣсѧць (měsęcĭ).  Twelvemonth is a noun; the noun plural is twelvemonths.

The adverb was twelvemonthly which is not the same as twelve-monthly, another ill-defined construction which originally meant one thing annually done but was used by some in the sense of something done every month of the year.  It’s now regarded as an archaic or dialect word for year and seen only in historic texts or as a literary device. In the mid-twentieth century there was movement among some to offer it as a way offering more precision in language, the notion being that year would describe a calendar year (eg 1999) whereas September 1998-August 1999 would be a twelvemonth.  The idea never caught on.

Year (pronounced yeer)

(1) A period of 365 or 366 days, in the Gregorian calendar, divided into twelve calendar months, now reckoned as beginning 1 January and ending 32 December (the calendar or civil year).  The 366 day leap year happens (with a few exceptions) every four years; 29 February being the quadrennial addition.  The leap year (mostly) fixes the calendar and maintains it at the same length, mechanics of adjustments described in Medieval Latin as saltus lunae (omission of one day in the lunar calendar every 19 years) which in the Old English was monan hlyp. 

(2) A period of approximately the same length in other calendars; The traditional Chinese calendar, which determines the date of the Lunar New Year, is lunisolar (based on the cycle of the moon as well as on Earth's course around the sun).  A month on this Chinese calendar is 28 days long, and a normal year lasts between 353-355 days.  Other methods of calculation include from Tishiri 1 to Elul 29 in the Jewish calendar, and from Muharram 1 to Dhu al-Hijjah 29 or 30 in the Islamic.

(3) A period of 12 calendar months calculated from any point.

(4) In astronomy, also called the lunar year, a division of time equal to twelve lunar months and equal to 354.3671 days

(5) In astronomy, as tropical year (also known as a solar or astronomical year), the time the Sun takes to return to the same position in the cycle of seasons, as seen from Earth and equal to 365.242 (eg the time from vernal equinox to vernal equinox, or from summer solstice to summer solstice).

(6) In astronomy, as sidereal year, the time taken by the Earth to orbit the Sun once with respect to the fixed stars (equal to 365.256).  Hence, it is also the time taken for the Sun to return to the same position with respect to the fixed stars after apparently travelling once around the ecliptic; the time in which any planet completes a revolution round the Sun (eg the Martian year).

(7) With various modifiers (fiscal year, liturgical year, academic year et al), a period out of every twelve months, devoted to a certain pursuit, activity, or the like.

(8) A group of students entering school or college, graduating, or expecting to graduate in the same year (as in class of 2020).

(9) In English common law as legal year, a measure equal to a year and a day, the period fixed to ensure the completion of a full year. It was used in admiralty law to determine the time within which wrecks had to be claimed and in the criminal law to determine liability in murder cases; if the victim of an assault lived a year and a day from the assault, the perpetrator could not be charged with murder, even were the victim subsequently to die from his injuries.  The rule was translated to statute law in some jurisdiction and was repealed only because of advances in medical care and technology.

Pre 900: From the Middle English yeer, from the Old English gēar, gearlic & gear (yearly, of the year, annual).  It was related to the Gothic jēr, the Old Saxon & Old High German jār, the Old Norse ār (year), the Polish jar (springtime), the Latin hōrnus (of this year), the Dutch jaar, the German Jahr, the Gothic jēr and the Greek hôros (hṓrā) (year, season, part of a day, hour).  The alternative spellings were yeare, yeer, yeere & yere, all long obsolete.  Year & yearling are nouns and yearly is a noun, adjective & adverb; the common noun plural is years.

Twelvemonth does still get the odd use, usually as a novelty or deliberate anachronism.

Year-long (also yearlong) dates from 1813, year-round from 1917 and as an adverb from 1948.  The light-year (also lightyear), the distance light travels in one year (circa 5.87 trillion miles (944 trillion km)) was first defined in 1888.  Yearling (an animal a year old or in its second year) is attested from the mid-fifteenth century, the noun year-old in this sense being from the 1530s.  Yearbook (also year-book) dates from the 1580s as (book of reports of cases in law-courts for that year), the sense extended to other books of “accumulated events and statistics of the previous year" by 1710.  The first used in the sense of a “graduating class album" is attested from 1926, an invention of American English.  The Dutch schrikkeljaar (leap year) is from the Middle Dutch schricken (leap forward) which translates literally as "be startled, be in fear" and the 29 February is schrikkeldag.  The Danish skudaar & Swedish skottår translate literally as "shoot-year”; The German schaltjahr is from schalten (insert, intercalate) and the Late Latin phrase was annus bissextilis, source of the Romanic words.  One quirk in modern commerce is that payrolls tend to be administered in weekly or multiples of weekly cycles and for most purposes there are 52 weeks in a year.  However, the year (to four decimal places) is actually about 52.1775 weeks long so, every thirteen years-odd, accountants often have to ensure provision has been made for an additional payroll period; modern software has solved the problem for most.

Many rules have been suggested to avoid any ambiguity when writing the year in text but the best method is simply to write if out in full (1999-2002).  There have been publications with rules which differ under different circumstances but any technical need to limit the number of characters used has long gone and the simple form avoids any ambiguity.  Should the need arise of to write using the tags BD and AD, it also important to choose a style that avoids ambiguity.  AD (anno domini (Latin: in the year of the lord), refers to the birth of Jesus Christ, the year 1 AD (somewhat inaccurately but notionally) being his year of birth, and anything tagged BC (before Christ) being the years prior, counted backwards and starting at 1 BC, there being no year zero (which is a nuisance because it means not all the twentieth century consists of years numbered 19xx, the last year of the century being 2000; 1 January 2001 being the first day of the new century and millennium).  Classically, the convention in English was to place the letters BC after the year and AD before.  That was so the written word would pay tribute to the spoken, the common expression in formal and ecclesiastical use being "in the year of our Lord 2021".  That’s now rare and it may be preferable to use the suffixed (55 BC, 2021 AD) for both.  The alternatives to BC &AD are BCE (before common era) & CE (common era), the years exactly aligned and, although there seems no accepted convention about where the letters are placed, use should be consistent.