Pro·​te·​ro·​zo·​ic | \ ˌprä-tə-rə-ˈzō-ik How to pronounce Proterozoic (audio) , ˌprō- \

Definition of Proterozoic

: of, relating to, or being the eon of geologic time or the corresponding segment of rocks that includes the interval between the Archean and Phanerozoic eons, exceeds in length all of subsequent geologic time, and is marked by rocks that contain fossils indicating the first appearance of eukaryotic organisms (such as algae) — see Geologic Time Table

Other Words from Proterozoic

Proterozoic noun

First Known Use of Proterozoic

1887, in the meaning defined above

History and Etymology for Proterozoic

Greek proteros former, earlier (from pro before) + -zoic — more at for

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The first known use of Proterozoic was in 1887

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Last Updated

4 Oct 2021

Cite this Entry

“Proterozoic.” Dictionary, Merriam-Webster, Accessed 28 Oct. 2021.

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More from Merriam-Webster on Proterozoic

Nglish: Translation of Proterozoic for Spanish Speakers


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