Definitions

1. adjective

relating to or denoting the earliest of the three eons of the Earth’s history, extending from about 541 to 252 million years ago and including the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian periods.

“The palaeozoic era saw the emergence of many diverse animal species.”

2. noun

a rock or deposit of palaeozoic age.

“The palaeozoic rocks found in the area date back millions of years.”