the.com/mesozoic

means The geological era, roughly 252 to 66 million years ago, when dinosaurs dominated the land, sea, and sky before an asteroid ended the party.

from Built from Greek 'mesos' (middle) and 'zoion' (animal) — literally 'middle life' or 'middle animals.' It's the middle chapter of a three-part scheme coined by 19th-century geologists slotting Earth's history into Paleozoic (ancient life), Mesozoic (middle life), and Cenozoic (recent life), based on the fossils layered in rock.