Epoch

Epoch (pronounced ep-uhk or ee-pok)

(1) A particular period of time marked by distinctive features, events etc.

(2) The beginning of a distinctive period in the history of anything.

(3) A point in time distinguished by a particular event or state of affairs; a memorable date.

(4) In geology, any of several divisions of a geologic period during which a geologic series is formed (much associated with rock formation).  An epoch (the shortest division of geologic time) is a sub-division of a period.  As a geochronologic unit, an epoch can range between hundreds of thousands to millions of years.

(5) In astronomy, an arbitrarily fixed instant of time or date, usually the beginning of a century or half century, used as a reference in giving the elements (such as coordinates of a planetary orbit) relating to a celestial body.

(6) In astronomy, the mean longitude of a planet as seen from the sun at such an instant or date.

(7) In chronology, astronomy & computing, a specific instant in time, chosen as the point of reference or zero value of a system that involves identifying instants of time.

(8) In physics, the displacement from zero at zero time of a body undergoing simple harmonic motion (the displacement of an oscillating or vibrating body at zero time).

(9) In AI (artificial intelligence), one complete presentation of the training data set to an iterative machine learning algorithm.

1605-1615: From the Medieval Latin epocha, from the Ancient Greek ἐποχή (epokhḗ) (epochē) (a check, cessation, stop, pause, fixed time, epoch of a star (ie the point at which it seems to halt after reaching the highest, and more generally the place of a star (thus the extension of use to “a historical epoch”))), from ἐπέχω (epékhō, (to hold in, check), the construct being ἐπι- (epi-) (upon) + ἔχω (ékhō) (to have, hold), from the primitive Indo-European root segh- (to hold).  The early seventeenth century adoption in English of epocha was in the sense of “point marking the start of a new period in time” and it was used by scholars and theologians of momentous events in history (the crucifixion of Christ; the Visigoths gathering at the gates of Rome etc).  Less than a decade after epocha had entered the language, the transferred meaning “a period of time” was in use and it entered the jargon of geology in 1802 although the technology then did not permit precise measurements and exploration was then embryonic (what are now understood as dinosaur fossils not so classified until 1824) so most of the early estimates of geological epochs were inaccurate.

Confusingly, “epoch” can be used either to refer to a distinct and defined historic period (ie with an agreed beginning & end) or the event associated with the beginning of that period.  The latter concept is best understood in the adjectival forms “epoch-making” and “epochful”.  Subepoch is a technical term from geology, used as a geochronologic unit comprising one or more ages, being a period of generally agreed significance within an epoch.  The companion superepoch (two or more sequential epochs references as one for illustrative or didactic purposes is non-standard.  In statistical analysis, sub_epoch, base-epoch, super_epoch & primary_epoch exist as commands in aspects of database handling and manipulation, the link being the use of “datum” as epoch’s coordinate term in cartography and engineering.  The alternative form epocha was in use between the seventeenth & nineteenth centuries.  Epoch is a noun & verb, epochful, epocjless & epochal are adjectives and epochally is an adverb; the noun plural is epochs.

Bal du moulin de la Galette (Dance at Le Moulin de la Galette, 1876), oil on canvas by Pierre-Auguste Renoir (1841–1919), Musée d'Orsay, Paris

The Belle Époque (appearing in texts often as La Belle Époque with capitalization not always used) was a period in European history characterized by peace, progress, cultural refinement and artistic innovation; the term was an adoption of the French La Belle Époque (literally “the beautiful era” and best understood as “the golden age”).  Historians date the start of the Belle Époque from the end of the Franco-Prussian War (1970-1871) although, “on the ground” it likely wasn’t so clear-cut because the impositions of war reparations made the first few post-war years “difficult” in France so “mid-1870s” may be a better point of origin.  The Belle Époque lasted until the blast of World War I (1914-1918) destroyed the continent’s sense of optimism and ended an era characterized by what might now be call an “end of history” feeling that held things like wars, famines and plagues were in the past and the future would be one of progress and improvement.

Art Nouveau.

An advertisement (1899) for Moët & Chandon's champagnes, designed by Czech painter & graphic artist Alphonse Mucha (1860–1939):  “White Star” champagne (left) & “Grand Crémant Imperial” (right).  The product is very much a period piece, Art Nouveau characterized by swirling shapes, stylized representations of women and intricate floral motifs.  For those with enough disposable income, La Belle Époque must have been an amusing time to live.  The “modern industrial” sense later summoned by the straight, sharp and geometric lines of Art Deco was a deliberate rejection of Art Nouveau's intricate, hand-crafted aesthetic yet in Art Deco the influence of the earlier style often is apparent.  Although by the 1920s unfashionable and in the inter-war years casually dismissed by many critics and historians, Art Nouveau's popular appeal never went away.  While there was never really a “revival”, the style's motifs remained a staple of commercial graphic art and the various “nostalgia movements” before being “cherry picked” by pop art, psychedelia and postmodernists.   

Those 40-odd years of what came to be called La Belle Époque were not without conflict or economic disruptions and it must be remembered Europe’s “golden age” was one of untroubled pleasure only for a select few, most of the population living lives of hard labor and drudgery, many on a variation of the Hobbesian (the very clever and deliciously wicked English philosopher Thomas Hobbes (1588-1679)) path: “nasty, crowded, brutish and short”.  La Belle Époque is a selective construct of the era’s intellectual and aesthetic landmarks in art, literature and architecture, characterized by opulence, eclecticism and an undeniable dynamism from which emerged movements such as Futurism, Cubism and Art Nouveau.  Viewed from our troubled times, the Belle Époque exists in a warm nostalgic glow and it’s telling the term first gained popularity in France during the 1930s, the decade of the Great Depression.  Even then, La Belle Époque was still in living memory but because it became mythologised as a “golden age”, it was as myth it passed into history.

Lindsay Lohan entering her fifth decade.  Her five eras thus far may loosely be labelled: (1) child star, (2) troubled Hollywood starlet, (3) nemesis, (4) reinvention and (5) redemption.

Signed to the Ford agency, Lindsay Lohan secured her first modelling gig aged three but what’s understood as the “Lindsay Lohan era” ran for the decade after the release of Mean Girls (2004).  It was characterized by her low-speed car crashes, court appearances and becoming a staple of the tabloid press and lower reaches of the glossy magazine industry, a reasonable contribution to GDP (gross domestic product), providing predictable cash flow for paparazzi on both sides of the Atlantic.  Improbable as it once seemed, she proved a survivor in the churn of the industry's destructive “child star” machine and on 2 July, 2026 celebrated her 40^th birthday.  That happened during the 23^rd FIFA (Fédération Internationale de Football Association (the International Federation of Association Football which, for historic reasons, recognizes more countries than the UN (United Nations)) World Cup and, on the day, playing at the Bay Area Stadium in Santa Clara, San Francisco, USA beat Bosnia-Herzegovina 2-0 so that was a good birthday present.  

Geologyin's illustration of the concept of geological epochs.

In scientific usage there is precision, the ICS (International Commission on Stratigraphy) codifying a strict hierarchy on the discipline of geology, the structure being Eon → Era → Period → Epoch → Age.  However, in ordinary English discourse (and even in the work of professional scholars and historians) there is no fixed hierarchy in that an age may be longer than an era and an era may be longer than an epoch; unless following established conventions, writers can opt for whichever word best conveys the intended nuance, a choice that can be influenced by the search for rhetorical effect or the rhythm of the narrative.  So, in the way of English, there are no “rules” but, as a general principle, (1) Age = “known for...”, (2) Era = “lasting period of...” and (3) Epoch = “a period with a turning point that defined its nature.”  The overlaps in use don’t usually cause confusion but among the fastidious there are acknowledged nuances and accepted conventions of use:

(1) An epoch is a distinct period marked by particular characteristics or events, thus the use in geology where defining changes or sets of conditions can be established by scientific techniques such as chemical analysis or radiocarbon dating.  In non-scientific use, because of the etymological lineage, an epoch typically begins with some sort of event thought a turning point or watershed and this can be an organic development with no exact fixed date (the Industrial Revolution) or something decidedly exact (the epoch of the computer operating system Unix is defined as 00:00:00 UTC, 1 January 1970 although this was not first set precisely then).

(2) An age is a period with a specific, dominant association.  That might be a technology (bronze age; oil age; jet age etc), a characteristic (age of empires; age of European colonialism etc) or an individual (Napoleonic age; Elizabethan Age etc).  Unlike the epochs of geologists and astronomers, “ages” can run in parallel or overlap.  While some are sequential such as the “Three Age System” (Stone Age; Bronze Age; Iron Age) tracking the evolution of humanity's tools and metalworking capabilities between prehistory and Antiquity, others can co-exist such as the Age of Sail & Age of Enlightenment.  Because of the nature of the word and historic pattern of use, of the three, “age” is the most flexible and adaptable because it’s merely associative, not exclusive and often with no precise chronology.

(3) An era is a period (by human standards usually but not necessarily long) with origins at a certain point (usually an event) and characterized by an enduring pattern; eras tend to be major historical phases or systems (the Nazi era; the analogue era etc).  Generally “era” is used to denote something coherent (though it need not be long); a stretch of history with a recognizable character, a beginning and an end.  That can reference the life of an individual (Queen Victoria lent her name to the “Victorian era” 1837-1901), several individuals (there were four Kings of England named George whose collective reign defined the “Georgian era” 1714-1830) or a specific closed-time set (the “inter war era”: 1918-1939).

Eras tour merchandise.  Canvas tapestry featuring photographs from Taylor Swift’s The Eras Tour, cotton canvas, 800 mm (31½ inches) x 1220 mm (48 inches).

Taylor Swift’s “Eras” project tends to be thought of as a concert tour but it’s better imagined as pop culture’s greatest ever exercise in vertical integration, a merging of music (audio streaming, packaged (in multiples in the case of the vinyl releases) & live performance), video content, merchandise ranging from framed posters, a “limited edition” book, a film with concert footage, outfits emulating those worn on stage, jewellery, hoodies, pillows, stainless steel tumblers and more.  Although there has in recent years been a bit of mission creep, the idea of a canvas tapestry as a piece of tour merchandise in the pop music business would, until recently, likely have occurred to few.  Commerce has moved on from a half-century earlier when, at a Led Zeppelin concert, one might be able to buy a Tee-shirt (in S, M, L & XL), maybe with a choice of black or white (black quickly selling out).

Ms Swift is good with words and for the “Eras” project may have pondered using “Ages” or “Epochs”.  Given the accepted conventions (Age = “known for...”, Era = “lasting period of...” and Epoch = “a period with a turning point that defined its nature.”) and the concept of the “Eras” project, a convincing case could have been made for “Ages” because each subset was thematically distinct while the use of “Epochs” would have worked because the word is understood as a “period of time with a beginning and end” but linking each with a single “triggering event” might have descended to abstractions so “Eras” seems the best choice.  Certainly it’s unlikely she long considered using “Periods”; although etymologically defensible, it would have been decarded on much the same basis as that of the publishers of the magazine Australian Women’s Weekly who, upon in 1983 switching to issuing monthly editions, opted not to change the title to “Women’s Monthly”.

There is of course a vagueness associated with the definitions because not all “eras” and “ages” have as convenient bookends the end of one war and the start of another; that’s why context can matter.  In speaking of the time after World War II (1939-1945), “post-war era” is a common term but the meaning can vary depending on what’s being discussed.  It’d be absurd to speak of 2026 as being in the “post-war” era (although in a sense that’s true) so meaning must be gleaned from context.  The two decade period 1918-1939 came to be called both the “inter-war” and “pre-war” era (although many tend to restrict the latter to a start-point in the mid-1930s) and in much historiography there's sometimes the suggestion the “post-war” era can usefully be said to have ended some 20 years hence; that’s about 1965 so conveniently (1) in the new era of the High Cold War, (2) about the length of a then typical “generation” and (3) in the 1960s, a very different era.  So it can be inexact and some with a focus on political economy fix the end date on exactly 17 October 1973, the day OAPEC (Organization of Arab Petroleum Exporting Countries) proclaimed an oil embargo targeting the US and other states providing military aid to Israel during the 1973 Yom Kippur War.  At that point, the West’s long post-war boom, although already stuttering, ended.  In a similar vein, although also very much a Western-centric view, some historians have argued the nineteenth century is best imagined as a construct running from the close of the Congress of Vienna (1814-1815) to the outbreak of World War I (1914-1918).  There’s much support for that although there are different views about the conceptual view of the twentieth century. While 1914 seems a logical starting-point, candidates for the end date include 1989 (fall of the Berlin Wall (1961-1989)), 1991 (dissolution of the Soviet Union (1922-1911)) and the 9/11 terrorist strikes in 2001.

Taylor Swift Style: Fashion through the eras.

Between March 2023 and December 2024, Taylor Swift’s “Eras” tour took in 149 shows in 51 cities over five continents; each performance ran for a remarkable 3½ hours and there was a mid-tour revision of the song set to interpolate material The Tortured Poets Department (2024), her eleventh studio album.  The “Eras” title was an allusion to the show’s format, a retrospective in which each of her albums was designated as a “musical era”, the many outfits worn tied to those themes and just as each song and each performance was a product, so could be each outfit, some available on-line for purchase by devoted Swifties.  So, as set piece events go, Ms Swift set a high bar and, on revenues in excess of US$2 billion, profits were high and continue to grow.

Even when there are precise start and end dates, things can at the margin become blurred.  Pedants enjoy pointing out the 1960s began on 1 January 1961 so an expression like “the 1960s” ends on 31 December 1969 but the decade in which most of those years existed actually includes 1970, a quirk which extends also to centuries and millennia, something ultimately a product of there being no year zero in the calendar now defining BCE (before Common Era) and CE (Common Era) (the pair the secular version of BC (Before Christ) and AD (from the Latin Anno Domini (in the year of the Lord)), all based on the (nominal) birth date of Jesus Christ.  “Ages” and “eras” can at once be “exact” and “indicative”.  Many of the civilizations of antiquity all had their so-called “golden ages” and these tended to be associated with particular dynasties or reigns.  The examples are many and are cross-cultural, including the Gupta Empire in India (mid-third to mid-sixth century AD) founded by Mahārāja Śrī-Gupta, the Tang dynasty (626-684) & the reign of Tae-tsong (618-626) in China and, in Egypt, the reigns of Sethos I and Ram'eses II (1336-1224 BC).  In the West, the use of “golden ages” is legion including in Russia during the rule of Czar Peter the Great (1672-1725) (memorable because the Russian people have not enjoyed many “golden ages”) and, of course, in England, the “Elizabethan age”, referencing the reign of Elizabeth I (1533–1603; Queen of England & Ireland 1558-1603).  However, at the granular level, the idea of the term “Elizabethan age” denoting a “golden age” in literature was contested by the English writer, literary scholar and Anglican lay theologian C. S. Lewis (1898–1963) who, in his Introduction to English Literature in the Sixteenth Century (1654), distinguished the “estimable” literature of the later Elizabethan period from what he called that of the earlier “drab age”.  Lewis found drabness in the poetry and prose of the later medieval period up to the early Renaissance, distinguishing it from the “golden era style” between circa 1580-1603.  Lewis was an uncompromising critic but while most in the profession may well agree much that was written in the fifteenth century and early Tudor period was “drab”, among those published in the period were Sir Thomas Wyatt (1503-1542) and John Skelton (circa 1460-1529); their writing was not beyond criticism but the works were hardly drab.

Sarah Chapelle's (b 1992) Swiftie site documenting looks from The Eras tour: Fearless v6 (worn 18 October, 2024, far left), Midnights v5 (worn 16 August, 2024, centre left), 1989 v2 (worn 19 March, 2023, centre right) and Reputation v1 (worn 18 March, 2023, far right).  Some outfits can be purchased on-line but buyers should note they should not expect their appearance exactly to emulate what's “on the tin”.  

Simulacrum describes an image that while not purely realistic, maintains enough of a likeness for the subject to be recognizable.  In some jurisdictions it can be deemed “deceptive and misleading” if a product is represented in manner judged to be a “deliberate misrepresentation” intended to induce a purchase.  Legal recourse is available but is practical only if enough money is involved (such as real estate); although in theory someone purchasing a McDonalds Big Mac after being tempted by the image in the advertising might have grounds for an action, a claim of under $US10 would not impress a judge and even a class action would, on several grounds, be thrown out.  Presumably a disgruntled consumer could lodge a claim for the “pain & suffering” caused by one's Big Mac not looking as attractive as the one in the advertising but that'd likely anger the judge still more.  The classic simulacrums were the stylish images rendered in the 1960s by Art Fitzpatrick (1919–2015) & Van Kaufman (1918-1995) for GM’s (General Motors) PMD (Pontiac Motor Division) and those of Ms Swift in the Eras Tour outfits are in the same “mannerist but not quite surrealist” tradition.  Although obviously “unrealistic”, these depictions are not “deceptive and misleading” because they’re so obviously simulacral and exist only as devices, the extent of the licence taken illustrated by them appearing next to a flesh & blood Ms Swift in the same outfit.  They are “impossible” rather than “idealized”.

Super simulacrum: The Colossus of Rhodes (circa 1560), hand-colored by Dutch portrait and religious painter Maarten van Heemskerck (1498–1574) on an engraving by Dutch publisher & designer Philip Galle (1537–1612).

The Colossus of Rhodes was one of the Seven Wonders of the Ancient World and although it stood for barely half a century before being felled by an earthquake, it's ruins lying for almost a millennium as a kind of tourist attraction before the metal was carted of as scrap to be melted-down an re-cycled.  The notion the statue's legs straddled the entrance to Rhodes Harbor with tall-masted ships passing between them was wholly fanciful; even with modern materials and techniques, such a construction would be impossible.  The engineers and architects of the sixteenth century would of course have known it couldn't be done but such was the allure of the era of Classical Antiquity that brilliant myths seduced the public imagination better than tiresome facts.

Other “era-related” terminology also often used interchangeably relates to that long span of history between the fall of the Western Roman Empire (476 AD) and the dawn of the Renaissance in the late fourteenth century: (1) Middle Ages, (2) Dark Ages and (3) Medieval.  “Middle Ages” is the most obviously descriptive because it refers to the period between the dying gasps of Classical Antiquity and the cultural & artistic revival of the Renaissance while Medieval simply means “relating to the Middle Ages” (although by virtue of association and use, it came to be used also as a slur).  As general principle, historians tend to divide the Middle Ages into (1) Early (476-circa 1000), (2) High (circa 1000-circa 1300) and (3) Late (circa 1300-circa 1500).  “Dark Ages” reflected the prejudices of fifteenth century writers who regarded the earlier Middle Ages (476-circa 1000) as a period of stagnation, lack of progress and “intellectual darkness”, a stark contrast to the idealized vision of Classical Antiquity they constructed from what evidence there was, “filling in the gaps” with imaginations as famously vivid as any of the Medieval scribes and artists responsible for some fabulous beasts.  The Seven Wonders of of the Ancient World” they found especially compelling, some of their speculative depictions of the Colossus of Rhodes and the Walls and Hanging Gardens of Babylon such examples of architectural gigantism even Albert Speer (1905–1981; Nazi court architect 1934-1942; Nazi minister of armaments and war production 1942-1945) might have been embarrassed.  Maybe they looked in awe at the scale of Great Pyramid of Giza and assumed all the ancients operated in “think big” mode.

Tony Abbott (b 1957; Prime Minister of Australia 2013-2015) agitprop.

Mr Abbott's combination of relentless negativity and repetition of 3WSs (three word slogans) made him one of his generation's most effective leaders of the opposition.  In office, the results were mixed and it ended badly.  Although medieval may literally mean “relating to the Middle Ages” and can be used as a neutral adjective (medieval architecture, medieval manuscripts etc), it is also used as a term of derision: “Mr Abbott’s views on certain topics seem distinctly medieval although, to be fair, the thirteenth century probably never produced a finer mind”.  Used in that way, it implies “outdated, harsh or unenlightened”, a throwback to the stereotypes of the Dark Ages but more recent scholarship has cast doubt on whether the “Dark Ages” was a time as culturally sterile and technologically stagnant and was for centuries an orthodoxy among historians.  A view now more popular is the earlier conceptions of the period were formed because of the relative scarcity of written records and although it’s now clear there was progress in agriculture, law, architecture, theology, literature, engineering and state formation, it is true that compared with what came before and what followed, progress often was fitful.  Of note also is there were in the Renaissance and beyond not a few who didn’t count “advances in theology” as progress worth mentioning.