Paleozoic

American  

[pay-lee-uh-zoh-ik, pal-ee-] / ˌpeɪ li əˈzoʊ ɪk, ˌpæl i- /

adjective

1. noting or pertaining to an era occurring between 570 million and 230 million years ago, characterized by the advent of fish, insects, and reptiles.

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noun

1. the Paleozoic Era or group of systems.

Paleozoic Scientific  

/ pā′lē-ə-zō′ĭk /

1. 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.

2. See Chart at geologic time

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Other Word Forms

• post-Paleozoic
  adjective
• pre-Paleozoic
  adjective

Etymology

Origin of Paleozoic

1830–40; paleo- + -zoic < Greek zōïkós pertaining to animals; see zo-, -ic

Example Sentences

See Examples For:

Paleozoic

Similar patterns appear repeatedly throughout the Paleozoic era after other extinction events driven by comparable environmental shifts.

From Science Daily ● Jan. 11, 2026

The fragment, reported today in Current Biology, dates back to the late Paleozoic Era, when many species began to emerge from the water to live on land.

From Science Magazine ● Jan. 11, 2024

Trilobites are early arthropods from the Paleozoic Era.

From Science Daily ● Dec. 21, 2023

When the going got tough in the Paleozoic Era, trilobites rolled up.

From New York Times ● Dec. 19, 2023

Sometimes too you will see the term Phanerozoic used to describe the span encompassing the Cenozoic, Mesozoic, and Paleozoic eras.

From "A Short History of Nearly Everything" by Bill Bryson