What is "epoch"

Epoch \Ep"och\ ([e^]p"[o^]k or [=e]"p[o^]k; 277), n. [LL. epocha, Gr. 'epochh` check, stop, an epoch of a star, an historical epoch, fr. 'epe`chein to hold on, check; 'epi` upon + 'e`chein to have, hold; akin to Skr. sah to overpower, Goth. sigis victory, AS. sigor, sige, G. sieg: cf. F.

1. A fixed point of time, established in history by the occurrence of some grand or remarkable event; a point of time marked by an event of great subsequent influence; as, the epoch of the creation; the birth of Christ was the epoch which gave rise to the Christian era.

   In divers ages, . . . divers epochs of time were used.
   --Usher.

   Great epochs and crises in the kingdom of God.
   --Trench.

   The acquittal of the bishops was not the only event which makes the 30th of June, 1688, a great epoch in history.
   --Macaulay.

   Note: Epochs mark the beginning of new historical periods, and dates are often numbered from them.

2. A period of time, longer or shorter, remarkable for events of great subsequent influence; a memorable period; as, the epoch of maritime discovery, or of the Reformation. ``So vast an epoch of time.''
   --F. Harrison.

   The influence of Chaucer continued to live even during the dreary interval which separates from one another two important epochs of our literary history.
   --A. W. Ward.

3. (Geol.) A division of time characterized by the prevalence of similar conditions of the earth; commonly a minor division or part of a period.

   The long geological epoch which stored up the vast coal measures.
   --J. C. Shairp.

4. (Astron.)

   1. The date at which a planet or comet has a longitude or position.

   2. An arbitrary fixed date, for which the elements used in computing the place of a planet, or other heavenly body, at any other date, are given; as, the epoch of Mars; lunar elements for the epoch March 1st, 1860.

      Syn: Era; time; date; period; age.

      Usage: Epoch, Era. We speak of the era of the Reformation, when we think of it as a period, during which a new order of things prevailed; so also, the era of good feeling, etc. Had we been thinking of the time as marked by certain great events, or as a period in which great results were effected, we should have called the times when these events happened epochs, and the whole period an epoch.

      The capture of Constantinople is an epoch in the history of Mahometanism; but the flight of Mahomet is its era.
      --C. J. Smith. [1913 Webster] ||

1610s, epocha, "point marking the start of a new period in time" (such as the founding of Rome, the birth of Christ, the Hegira), from Medieval Latin epocha, from Greek epokhe "stoppage, fixed point of time," from epekhein "to pause, take up a position," from epi "on" (see epi-) + ekhein "to hold" (see scheme (n.)). Transferred sense of "a period of time" is 1620s; geological usage (not a precise measurement) is from 1802.

n. A particular period of history, especially one considered remarkable or noteworthy.

1. n. a period marked by distinctive character or reckoned from a fixed point or event [syn: era]

2. (astronomy) the precise date that is the point of reference for which information (as coordinates of a celestial body) is referred [syn: date of reference]

3. a unit of geological time

An Epoch, epoch or EPOCH may refer to:

Epoch, in comics, may refer to:

• Epoch (DC Comics), a DC Comics time-traveling character
• Epoch (Marvel Comics), a Marvel Comics character, the offspring of Eon
• Epoch (Top Cow/Heroes and Villains), a comic series about a super-natural tournament featuring main character Jonah Wright

Epoch is a 2001 science fiction film directed by Matt Codd, starring David Keith, Stephanie Niznik, Brian Thompson, and Shannon Lee. In it, a strange monolith is discovered, and the team sent to study it encounters repeated disasters.

Epoch is an anthology of science fiction stories edited by Roger Elwood and Robert Silverberg, issued in hardcover by Berkley Putnam in 1975 and in paperback by Berkley in 1977.

In the fields of chronology and periodization, an epoch is an instant in time chosen as the origin of a particular era. The "epoch" then serves as a reference point from which time is measured. Time measurement units are counted from the epoch so that the date and time of events can be specified unambiguously.

Events taking place before the epoch can be dated by counting negatively from the epoch, though in pragmatic periodization practice, epochs are defined for the past, and another epoch is used to start the next era, therefore serving as the ending of the older preceding era. The whole purpose and criteria of such definitions are to clarify and co-ordinate scholarship about a period, at times, across disciplines.

Epochs are generally chosen to be convenient or significant by a consensus of the time scale's initial users, or by authoritarian fiat. The epoch moment or date is usually defined by a specific clear event, condition, or criterion — the epoch event or epoch criterion — from which the period or era or age is usually characterized or described.

In astronomy, an epoch is a moment in time used as a reference point for some time-varying astronomical quantity, such as the celestial coordinates or elliptical orbital elements of a celestial body, because these are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit.

The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodies) can be used to generate an ephemeris, a table of values giving the positions and velocities of astronomical objects in the sky at a given time or times.

Astronomical quantities can be specified in any of several ways, for example, as a polynomial function of the time-interval, with an epoch as a temporal point of origin (this is a common current way of using an epoch). Alternatively, the time-varying astronomical quantity can be expressed as a constant, equal to the measure that it had at the epoch, leaving its variation over time to be specified in some other way—for example, by a table, as was common during the 17th and 18th centuries.

The word epoch was often used in a different way in older astronomical literature, e.g. during the 18th century, in connection with astronomical tables. At that time, it was customary to denote as "epochs", not the standard date and time of origin for time-varying astronomical quantities, but rather the values at that date and time of those time-varying quantities themselves. In accordance with that alternative historical usage, an expression such as 'correcting the epochs' would refer to the adjustment, usually by a small amount, of the values of the tabulated astronomical quantities applicable to a fixed standard date and time of reference (and not, as might be expected from current usage, to a change from one date and time of reference to a different date and time).

In geochronology, an epoch is a subdivision of the geologic timescale that is longer than an age and shorter than a period. We are currently living in the Holocene Epoch of the Quaternary Period. Rock layers deposited during an epoch are called a series. Series are subdivisions of the stratigraphic column that, like epochs, are subdivisions of the geologic timescale. Like other geochronological divisions, epochs are normally separated by significant changes in the rock layers to which they correspond.

Epochs are most commonly used for the younger Cenozoic Era, where a greater collection of fossils has been found and paleontologists have more detailed knowledge of the events that occurred during those times. They are less commonly referred to for the other eras and eons, since less fossil evidence exists that allows us to form a clearer view of those time periods.

Epoch was a Russian literary magazine published in 1864-65 by Fyodor Dostoyevsky and his brother Mikhail.

Epoch is a joint comic book venture of Top Cow Productions and Heroes and Villains Entertainment.

Epoch, also known as The Lord of Time, is a comic book fictional character published by DC Comics. He first appeared in Justice League of America #10 (March 1962) and was created by writer Gardner Fox and artist Mike Sekowsky.

A powerful being from the year 3786, the Lord of Time attacks the Justice League of America, using his chrono-cube to peel back the fourth-dimensional veil of time. Since his initial defeat by the JLA, this fugitive from the future learned to move laterally and diagonally through history, accessing armies and armaments spanning millions of years. He desires to conquer space and time. To make sure his bid to rule all reality is successful, he is capable of eliminating the JLA's ancestors, erasing them from existence. At some point, the Lord of Time created a frozen moment in history called Timepoint, and he will eventually evolve into a being known as Epoch who desires to master the timestream, changing events to grant him power.

Epoch seemingly died in the JLA/ WildC.A.T.s crossover. However, he recently returned, once again as the Lord of Time, in the The Brave and the Bold series. Epoch also made an appearance in the Justice League of America 80-Page Giant #1 comic (November 2009), where he battled the JLA and tossed all the superheroes back in time.

Epoch is a triannual American literary magazine founded in 1947 and published by Cornell University. It has published well-known authors and award-winning work including stories reprinted in The Best American Short Stories series and poems later included in The Best American Poetry series. It publishes fiction, poetry, essays, graphic art, and sometimes cartoons and screenplays, but no literary criticism or book reviews.

Epoch is staffed by faculty and graduate students from the English Department creative writing program, and edited by Michael Koch. Epoch appears in September, January, and May, with issues generally running 128 to 160 pages.

EPOCH is an intensive chemotherapy regimen intended for treatment of aggressive non-Hodgkin's lymphoma.

It is often combined with rituximab. In this case it is called R-EPOCH or EPOCH-R.

[R]-EPOCH regimen consists of:

1. (R)ituximab: an anti- CD20 monoclonal antibody, which has the ability to kill B cells, be they normal or malignant;
2. (E)toposide: a topoisomerase inhibitor from the group of epipodofyllotoxins;
3. (P)rednisolone: a glucocorticoid hormone that can cause apoptosis and lysis of both normal and malignant lymphocytes;
4. (O)ncovin, also known as vincristine: a vinca alkaloid that binds to the protein tubulin, thereby preventing the formation of microtubules and mitosis;
5. (C)yclophosphamide: an alkylating antineoplastic agent;
6. (H)ydroxydaunorubicin, also known as doxorubicin: an anthracycline antibiotic that is able to intercalate DNA, damaging it and preventing the cell division.