1. A geological era from about 541 million to 252 million years ago, characterized by the evolution of marine invertebrates, fish, amphibians, and early reptiles
   - Paleozoic, Paleozoic era

1. Of or relating to or denoting the Paleozoic era
   "Palaeozoic fossils provide crucial information about the evolution of early life forms";
   - Paleozoic

Type of: era, geological era

Encyclopedia: Palaeozoic