Definitions for "Palaeozoic"
'Ancient life'. A geological era from 600 to 245 million years ago, including periods such as the Devonian and Carboniferous.
An era of geological time, dating from about 550 to 250 million years ago (comprising the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian periods).
Era of geologic time 225-570 million years ago.
The oldest system of fossiliferous rocks.