An era is a long period of time with different technical and colloquial meanings, and usages in language. It begins with some beginning event known as an epoch, epochal date, epochal event or epochal moment (the latter in particular referring to a great deal of precision as in astronomy). When era is extended to a calendar system, it is known as a calendar era. Look up epoch in Wiktionary, the free dictionary. ... In chronology, an epoch (or epochal date, or epochal event) means an instant in time chosen as the origin of a particular era. ... In chronology, an epoch (or epochal date, or epochal event) means an instant in time chosen as the origin of a particular era. ... This article or section is in need of attention from an expert on the subject. ... A calendar era is the year numbering system used by a calendar. ...

Uses

In chronology, an era is the highest level for the organization of the measurement of time. A calendar era indicates a span of many years which are numbered beginning at a specific reference date (epoch), which often marks the origin of a political state or cosmology, dynasty, ruler, the birth of a leader, or another significant historical or mythological event; it is generally called after its focus accordingly as in Victorian era. For the novel by Michael Crichton, see Timeline (novel). ... Look up time in Wiktionary, the free dictionary. ... A calendar era is the year numbering system used by a calendar. ... In chronology, an epoch (or epochal date, or epochal event) means an instant in time chosen as the origin of a particular era. ... Cosmology, from the Greek: κοσμολογία (cosmologia, κόσμος (cosmos) order + λογια (logia) discourse) is the study of the Universe in its totality, and by extension, humanitys place in it. ... The Victorian era of the United Kingdom marked the height of the British Industrial Revolution and the apex of the British Empire. ...

The word era also denotes the units used under a different, more arbitrary system where time is not represented as an endless continuum with a single reference year, but each unit starts counting from one again, as if time starts again. Such rather impractical system — a nightmare for historians once a single piece of the puzzle is missing — is the use of regnal years, which often reflects the preponderance in public life of the absolute ruler in many ancient cultures, while such tradition sometimes outlives the political power of the throne. Regnal year: the year of the reign of a sovereign. ...

In East Asia, each emperor's reign may be subdivided into several reign periods, each being treated as a new era. The name of each was a motto or slogan chosen by the emperor. Different East Asian countries utilized slightly different systems, notably: East Asia Geographic East Asia. ...

• Chinese Eras
• Japanese Eras
• Korean Eras
• Vietnamese Eras

A similar practice survived in the United Kingdom until quite recently, but only for formal official writings: in daily life the ordinary year A.D. was used since long, but Acts of Parliament were dated according to the years of the reign of the current Monarch, so that "61 & 62 Vict c. 37" refers to the Local Government (Ireland) Act 1898 passed in the session of Parliament in the 61st/62nd year of the reign of Queen Victoria. A Chinese era name (traditional Chinese: ; simplified Chinese: ; pinyin: ) is the era name, reign period, or regnal title used when traditionally numbering years in an emperors reign and naming certain Chinese rulers (see the conventions). ... Japanese era name (年号, nengō, lit. ... Korean era names were used during the period of Silla, Goguryeo, Balhae, Taebong, Goryeo, Joseon, and the Korean Empire. ... Below is a list of Vietnamese monarchs. ... In Westminster System parliaments, an Act of Parliament is a part of the law passed by the Parliament. ... The British monarch or Sovereign is the monarch and head of state of the United Kingdom and its overseas territories, and is the source of all executive, judicial and (as the Queen-in-Parliament) legislative power. ... The Local Government (Ireland) Act 1898 a piece of legislation passed as an Act of Parliament by the Parliament of the United Kingdom in 1898, to establish a system of local government in Ireland on lines similar that had been recently created in Great Britain at the time. ... Type Bicameral Houses House of Commons House of Lords Speaker of the House of Commons Michael Martin MP Lord Speaker Hélène Hayman, PC Members 1377 (646 Commons, 731 Peers) Political groups Labour Party Conservative Party Liberal Democrats Scottish National Party Plaid Cymru Democratic Unionist Party Sinn Féin... Queen Victoria redirects here. ...

In common speech and various contexts, the term era is also used, by extension, for any (as a rule relatively long) period in history with a name, often relating to common characteristic(s), even if this is not the normal way to organize time. The most relevant type are politic periods, for example: the Roman era, the Elizabethan era, the Victorian era (dynastic criteria, only formally correct within the British realm/empire/Commonwealth) and the Soviet era, or comparable literary notions like the Biblical era. Elizabethan redirects here. ... The Victorian era of the United Kingdom marked the height of the British Industrial Revolution and the apex of the British Empire. ... Soviet era is the period of Russian history comprising the years 1917 – 1991, when the power was held by the Communist Party of the Soviet Union. ...

The word era is also popularly used to denote the passing of — often shorter — periods that are only defined in terms of a specific discipline of sphere of life, such as the prominence of an artistic style, or more specifically in music, see musical eras, described in History of music, such as the Big Band era, Disco era. An event such as the death of Frank Sinatra is poetically called the end of an era. For other uses, see Music (disambiguation). ... For the academic study of history of music, see Music history. ... A big band is a type of musical ensemble associated with playing jazz music and which became popular during the Swing Era from the early 1930s until the late 1940s, although there are many big-bands around nowadays. ... Discothèque redirects here. ... Sinatra redirects here. ...

• In natural science, there is need for another time perspective, independent from human activity, and indeed spanning a far longer period (mainly prehistoric), as in Geology where era refers to four well-defined time spans covering the entire existence of the planet Earth: from oldest to youngest, these are the Proterozoic, Paleozoic, Mesozoic, and Cenozoic eras, each subdivided in shorter periods; see Geologic timescale for a slightly different interpretation and details.

In astronomy the periods are even longer, to cover the entire existence of the universe (in the order of 13.7 billion years), but usually just denoted in numerical units, as there is no significant link to any earthly reality, our planet being astronomically insignificant (except as the only known observation point). This article includes a list of works cited but its sources remain unclear because it lacks in-text citations. ... A geologic era is a subdivision of geologic time that is a separate classification that divides the Phanerozoic Eon into three parts timeframes. ... This article is about Earth as a planet. ... The Precambrian (Pre-Cambrian) is an informal name for the supereon comprising the eons of the geologic timescale that came before the current Phanerozoic eon. ... The Palaeozoic is a major division of the geologic timescale, one of four geologic eras. ... The Mesozoic Era is one of three geologic eras of the Phanerozoic eon. ... The Cenozoic Era (pronounced ); sometimes Caenozoic Era or Cainozoic Era (in the United Kingdom), meaning new life (Greek (kainos), new, and (zoe), life), is the most recent of the three classic geological eras. ... The geologic time scale is used by geologists and other scientists to describe the timing and relationships between events that have occurred during the history of the Earth. ...

Etymology

The word has been in use in English since 1615, and is derived from Late Latin aera "an era or epoch from which time is reckoned," probably identical to Latin æra "counters used for calculation," plural of æs "brass, money".

The Latin word's use in chronology seems to have begun in 5th century Visigothic Spain, where it appears in the History of Isidore of Seville, and in later texts. The Spanish era is calculated from 38 BC, perhaps because of a tax (cfr. indiction) levied in that year, or due to a miscalculation of the Battle of Actium, which occurred in 31 BC. A votive crown belonging to Reccesuinth (653–672) The Visigoths (Latin: ) were one of two main branches of the Goths, an East Germanic tribe, the Ostrogoths being the other. ... Saint Isidore of Seville (Spanish: or ) (c. ... The Spanish era or Era of the Caesars refers to the dating system used in Hispania until the fourteenth century and the adoption of Anno Domini. ... An indiction is any of the years in a 15-year cycle used to date medieval documents. ... Combatants Octavian Mark Antony, Cleopatra VII of Egypt Commanders Marcus Vipsanius Agrippa Mark Antony Strength 260 warships, mostly liburnian vessels 220 warships, mostly quinqueremes and 60 egyptian warships Casualties Unknown Almost all of Antonys fleet The Battle of Actium was a naval battle of the Roman Civil War between...

Like epoch, "era" in English originally meant "the starting point of an age"; the meaning "system of chronological notation" is c.1646; that of "historical period" is 1741.

See also

• List of time periods

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