Phanerozoic

[fan-er-uh-zoh-ik]Geology

noun

the eon comprising the Paleozoic, Mesozoic, and Cenozoic eras.

adjective

of or relating to this eon.

Origin of Phanerozoic

1925–30; < Greek phaneró(s) manifest, visible + zo- + -ic

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for phanerozoic

Phanerozoic

adjective

of or relating to that part of geological time represented by rocks in which the evidence of life is abundant, comprising the Palaeozoic, Mesozoic, and Cenozoic eras

noun

the Phanerozoic the Phanerozoic era

Compare Cryptozoic

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

phanerozoic in Science

Phanerozoic

[făn′ər-ə-zō′ĭk]

The period of geologic time from about 540 million years ago to the present, including the Paleozoic, Mesozoic, and Cenozoic Eras. When this period of time was first defined, it was thought to coincide with the first appearance of life in the fossil record. It is now known that bacterial and other forms of life were present in the Precambrian Eon, and the Phanerozoic is understood to coincide with the appearance of life forms that evolved external skeletons. See Chart at geologic time.