| 释义 |
epoch
ep·och E0184900 (ĕp′ək, ē′pŏk′)n.1. A particular period of history, especially one considered remarkable or noteworthy.2. A unit of geologic time that is a division of a period.3. Astronomy An instant in time that is arbitrarily selected as a point of reference for specification of celestial coordinates.
[Medieval Latin epocha, measure of time, from Greek epokhē, a point in time; see segh- in Indo-European roots.]epoch (ˈiːpɒk) n1. a point in time beginning a new or distinctive period: the invention of nuclear weapons marked an epoch in the history of warfare. 2. a long period of time marked by some predominant or typical characteristic; era3. (Astronomy) astronomy a precise date to which information, such as coordinates, relating to a celestial body is referred4. (Palaeontology) geology a unit of geological time within a period during which a series of rocks is formed: the Pleistocene epoch. 5. (General Physics) physics the displacement of an oscillating or vibrating body at zero time[C17: from New Latin epocha, from Greek epokhē cessation; related to ekhein to hold, have] epochal adj ˈepˌochally advep•och (ˈɛp ək; esp. Brit. ˈi pɒk)
n. 1. a period of time marked by distinctive features, noteworthy events, changed conditions, etc.: an epoch of peace. 2. the beginning of a distinctive period in the history of anything. 3. a point of time distinguished by a particular event or state of affairs; a memorable date. 4. any of several divisions of a geologic period during which a geologic series is formed. 5. an arbitrarily fixed instant of time used as a reference in giving the elements of the orbit of a celestial body. [1605–15; < New Latin epocha < Greek epochḗ pause, check, fixed point in time] ep·och (ĕp′ək, ē′pŏk′) The shortest division of geologic time, being a subdivision of a period.epoch - Pronounced EH-puhk, it is from Greek epokhe, "fixed point in time, stoppage," and it was first the initial point in a chronology from which succeeding years were numbered.See also related terms for stoppage.epochA time unit within a geological period.Thesaurus| Noun | 1. |  epoch - a period marked by distinctive character or reckoned from a fixed point or eventeraperiod, period of time, time period - an amount of time; "a time period of 30 years"; "hastened the period of time of his recovery"; "Picasso's blue period"day - an era of existence or influence; "in the day of the dinosaurs"; "in the days of the Roman Empire"; "in the days of sailing ships"; "he was a successful pianist in his day"historic period, age - an era of history having some distinctive feature; "we live in a litigious age"modern era - the present or recent times | | 2. | epoch - (astronomy) an arbitrarily fixed date that is the point in time relative to which information (as coordinates of a celestial body) is recordeddate of referenceastronomy, uranology - the branch of physics that studies celestial bodies and the universe as a wholedate - the particular day, month, or year (usually according to the Gregorian calendar) that an event occurred; "he tried to memorizes all the dates for his history class" | | 3. | epoch - a unit of geological time that is a subdivision of a period and is itself divided into agesgeologic time, geological time - the time of the physical formation and development of the earth (especially prior to human history)geological period, period - a unit of geological time during which a system of rocks formed; "ganoid fishes swarmed during the earlier geological periods" |
epochnoun era, time, age, period, date, aeon the beginning of a major epoch in world historyepochnounA particular time notable for its distinctive characteristics:age, day, era, period, time (often used in plural).Translationsepoch (ˈiːpok) , ((American) ˈepək) noun (the start of) a particular period of history, development etc. The invention of printing marked an epoch in the history of education. 時代，新紀元 时代，新纪元 epoch
See also: Geologic Timescale (table)Geologic Timescale
Era Period Epoch Approximate duration
(millions of years)
Approximate number of years ago
(millions of years)
Cenozoic Quaternary Holocene 10,000 years ago to the present
Pleistocene 2 .
..... Click the link for more information. epoch, unit of geologic time that is a subdivision of a period. The Pleistocene and Holocene epochs, for example, are divisions of the Quaternary period. Epoch is also used to describe a short length of geologic time during a special occurrence, such as the glacial epoch. See geologygeology,
science of the earth's history, composition, and structure, and the associated processes. It draws upon chemistry, biology, physics, astronomy, and mathematics (notably statistics) for support of its formulations.
..... Click the link for more information. ; Geologic TimescaleGeologic Timescale
Era Period Epoch Approximate duration
(millions of years)
Approximate number of years ago
(millions of years)
Cenozoic Quaternary Holocene 10,000 years ago to the present
Pleistocene 2 .
..... Click the link for more information. (table).epoch An arbitrary fixed date or instant of time that is used as a reference datum, especially for stellar coordinates and orbital elements. For example, the coordinates right ascension and declination are continuously changing, primarily as a result of the precession of the equinoxes. Coordinates must therefore refer to a particular epoch, which can be the time of an observation, the beginning of the year in which a series of observations of an object was made, or the beginning of a half century. The standard epoch specifies the reference system to which coordinates are referred. Coordinates of star catalogs commonly referred to the mean equator and equinox of the beginning of a Besselian year. Since 1984 the Julian year has been used: the current standard epoch, designated J2000.0, is 2000 Jan. 1.5; it is exactly one Julian century removed from the standard epoch of 1900 Jan 0.5. Epochs for the beginning of a year now differ from the standard epoch by multiples of the Julian year. A standard epoch is usually retained for 50 years.epoch[′ep·ək] (astronomy) A particular instant for which certain data are valid; for example, star positions in an astronomical catalog, epoch 1950.0. (geology) A major subdivision of a period of geologic time. (physics) time epoch1. Astronomy a precise date to which information, such as coordinates, relating to a celestial body is referred 2. Geology a unit of geological time within a period during which a series of rocks is formed 3. Physics the displacement of an oscillating or vibrating body at zero time epoch (operating system)(Probably from astronomical timekeeping)A term used originally in Unix documentation for the timeand date corresponding to zero in an operating system'sclock and timestamp values.
Under most Unix versions the epoch is 1970-01-01 00:00:00 GMT;under VMS, it's 1858-11-17 00:00:00 (the base date of the USNaval Observatory's ephemerides); on a Macintosh, it's1904-01-01 00:00:00.
System time is measured in seconds or ticks past the epoch.Weird problems may ensue when the clock wraps around (seewrap around), which is not necessarily a rare event; onsystems counting 10 ticks per second, a signed 32-bit count ofticks is good only for 0.1 * 2**31-1 seconds, or 6.8 years.The one-tick-per-second clock of Unix is good only until2038-01-18, assuming at least some software continues toconsider it signed and that word lengths don't increase bythen. See also wall time.epoch (editor)(Epoch) A version of GNU Emacs for the X Window System from NCSA.epochThe starting date from which time is measured as a number of days or minutes or seconds, etc. In computer applications, epochs are used to maintain a time reference as a single number for ease of computation. Otherwise, depending on the granularity of time desired, every point in time would have to be stored with some of or all of the components of the time hierarchy, including year, month, day, hour, minute, second, millisecond, microsecond and nanosecond. Following are the various epochs in use. See also EPOC.
System Epoch Measured in Unix/Linux Jan. 1, 1970 Seconds Java Jan. 1, 1970 Milliseconds Windows files Jan. 1, 1601 Ticks (100 ns) Windows dates Jan. 1, 0001 Ticks (100 ns) Mac Jan. 1, 2001 Seconds Earlier Mac Jan. 1, 1904 Seconds Excel Dec. 31, 1899 Days DB2 Dec. 31, 1899 Days Unununium Jan. 1, 2000 Microseconds
 | | No USB Drives in 1969 |
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| When this USB drive was formatted, the date was reset to the epoch. The 7:00pm tells us it was done on the East Coast, five hours behind the UTC time of January 1, 1970 (see above). This info comes from the Mac that the drive was plugged into. |
epoch
epoch In clinical trials, the interval of time in the planned conduct of a study—the term epoch is intended to replace period, cycle, phase, stage and other temporal terms. An epoch is associated with a purpose (e.g., screening, randomisation, treatment, follow-up), and applies across all arms of the study.epoch (ĕp′ŏk) A measurable amount of time; e.g., the length of time used in standardized sleep studies (usually 30 sec to 1 min), or the duration of a particular geological or biological event, as indicated in earth sciences.EPOCH
| Acronym | Definition |
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| EPOCH➣End Physical Punishment Of Children | | EPOCH➣Excellence in Processing Open Cultural Heritage (EU Network of Excellence) | | EPOCH➣Etoposide, Prednisone, Vincristine, Cyclophosphamide, Doxorubicin (chemotherapy regimen) | | EPOCH➣European Parallel Operating System Based on Chorus | | EPOCH➣European Programme On Climate and Natural Hazards | | EPOCH➣Education Sustaining Peace through Open Learning and Accessible Community Engagement Habitats | | EPOCH➣Environmental Power Control Hardware |
epoch
Synonyms for epochnoun eraSynonymsSynonyms for epochnoun a particular time notable for its distinctive characteristicsSynonymsSynonyms for epochnoun a period marked by distinctive character or reckoned from a fixed point or eventSynonymsRelated Words- period
- period of time
- time period
- day
- historic period
- age
- modern era
noun (astronomy) an arbitrarily fixed date that is the point in time relative to which information (as coordinates of a celestial body) is recordedSynonymsRelated Wordsnoun a unit of geological time that is a subdivision of a period and is itself divided into agesRelated Words- geologic time
- geological time
- geological period
- period
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