Paleozoic

Pa·le·o·zo·ic  (pl--zk)

adj.

Of, belonging to, or designating the era of geologic time that includes the Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, and Permian periods and is characterized by the appearance of marine invertebrates, primitive fishes, land plants, and primitive reptiles. See Table at geologic time.

n.

The Paleozoic Era.

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Paleozoic  (pl--zk)

The era of geologic time from about 540 to 245 million years ago. The beginning of the Paleozoic Era is characterized by a great diversity of marine invertebrate animals. Primitive fish and reptiles, land plants, and insects also first appeared during this time. The end of the Paleozoic is marked by the largest recorded mass extinction in the Earth's history, which wiped out nearly 90% of known marine life forms. See Chart at geologic time.

Thesaurus

Noun	1.	Paleozoic - from 544 million to about 230 million years ago Paleozoic era Permian, Permian period - from 280 million to 230 million years ago; reptiles Carboniferous, Carboniferous period - from 345 million to 280 million years ago Age of Fishes, Devonian, Devonian period - from 405 million to 345 million years ago; preponderance of fishes and appearance of amphibians and ammonites Silurian, Silurian period - from 425 million to 405 million years ago; first air-breathing animals Ordovician, Ordovician period - from 500 million to 425 million years ago; conodonts and ostracods and algae and seaweeds Cambrian, Cambrian period - from 544 million to about 500 million years ago; marine invertebrates
Adj.	1.	Paleozoic - of or relating to or denoting the Paleozoic era