Pal ‧ ae ‧ o ‧ zo ‧ ic BrE AmE British English , Paleozoic American English /ˌpæliəˈzəʊɪk, ˌpeɪ- $ ˌpeɪliəˈzoʊ-/ adjective
belonging or relating to the period of time in the Earth's history, from about 570 million years ago to about 245 million years ago, when fish, insects, ↑ reptile s and some plants first started to exist ⇨ mesozoic