1. of, relating to, or denoting the eon of geologic time from about 541 million years ago to the present, characterized by the abundance and diversity of visible life forms
Usage: geology; often capitalized

1. the Phanerozoic eon; the most recent major division of geologic time
Usage: geology; often capitalized

Examples

• The Phanerozoic eon began with the Cambrian explosion of life.
• Fossils are abundant in Phanerozoic rocks because organisms had hard shells and skeletons.
• The Phanerozoic is divided into three major eras: the Paleozoic, Mesozoic, and Cenozoic.
• During the Phanerozoic eon, life diversified from simple organisms to complex animals and plants.
• Geologists study Phanerozoic sediments to understand the evolution of life on Earth.