-zoic¹

Relating to a given geological aeon or era.

Greek zōē, life, plus ‑ic.

Among other divisions of geological time are the Proterozoic aeon (Greek proteros, former) from about 2,500 million years ago to 570 million years ago, after which follows the Phanerozoic aeon (Greek phaneros, visible, evident), covering the whole of time since then; and comprising the Palaeozoic (Greek palaios, ancient), Mesozoic (Greek mesos, middle), and Cenozoic (Greek kainos, new) eras, the last of which began 65 million years ago.