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Of, relating to, or being the geologic time period between Hadean Time and the Cambrian Period, often subdivided into the Archean and Proterozoic Eras, comprising most of the earth's history and marked by the appearance of primitive forms of life. See Table at geologic time.
The Precambrian Eon.
(Geological Science) of, denoting, or formed in the earliest geological era, which lasted for about 4 000 000 000 years before the Cambrian period
or Pre-Cam•bri•an(priˈkæm bri ən, -ˈkeɪm-)
1. noting or pertaining to the earliest era of earth history, ending 570 million years ago, during which the earth's crust formed and life first appeared in the seas.n.
2. the Precambrian Era.
The span of geologic time between Hadean Time and the Phanerozoic Eon, from about 3.8 billion to 540 million years ago. During the Precambrian Eon, which is divided into the Archean and Proterozoic, primitive forms of life first appeared on Earth. See Chart at geologic time.
The period containing all of Earth’s history before the Cambrian period.
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|Noun||1.||Precambrian - the eon following the Hadean time and preceding the Phanerozoic eon; from about 3,800 million years ago until 544 million years ago|
Proterozoic, Proterozoic aeon, Proterozoic eon - from 2,500 to 544 million years ago; bacteria and fungi; primitive multicellular organisms