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An era is a span of time defined for the purposes of chronology or historiography, as in the regnal eras in the history of a given monarchy, a calendar era used for a given calendar, or the geological eras defined for the history of Earth. [1] Comparable terms are epoch, age, period, saeculum, aeon (Greek aion) [2] and Sanskrit yuga. [3]
For words to appear here, they must appear in their own entry in a dictionary; words that occur only as part of a longer phrase are not included. Proper nouns are not included in the list. There are, in addition, many place names and personal names, mostly originating from Arabic-speaking countries, Albania, or China, that have a Q without a U.
This category's scope is limited to human-related history since the end of Earth's most recent glacial period ("the Ice Age") around 10,000 to 15,000 years ago.. History portal
Homininaeid Era – Period prior to the existence of Homininae Homininid Era – Period prior to the existence of Hominini Prehistory – Period between the appearance of Homo ("humans"; first stone tools c. three million years ago) and the invention of writing systems (for the Ancient Near East : c. five thousand years ago).
An era is the second largest geochronologic time unit and is equivalent to a chronostratigraphic erathem. [ 14 ] [ 13 ] There are ten defined eras: the Eoarchean , Paleoarchean , Mesoarchean , Neoarchean , Paleoproterozoic , Mesoproterozoic , Neoproterozoic , Paleozoic , Mesozoic and Cenozoic , with none from the Hadean eon.
The Paleozoic ("old life") era was the first and longest era of the Phanerozoic eon, lasting from 538.8 to 251.9 Ma. [105] During the Paleozoic, many modern groups of life came into existence. Life colonized the land, first plants, then animals. Two significant extinctions occurred.
Common Era (CE) and Before the Common Era (BCE) are year notations for the Gregorian calendar (and its predecessor, the Julian calendar), the world's most widely used calendar era. Common Era and Before the Common Era are alternatives to the original Anno Domini (AD) and Before Christ (BC) notations used for the same calendar era. The two ...
In stratigraphy, paleontology, geology, and geobiology, an erathem is the total stratigraphic unit deposited during a certain corresponding span of time during an era in the geologic timescale.