Definitions

1. adjective

relating to the geologic time period from about 65 million to 2.6 million years ago, characterized by the emergence of mammals and the rise of modern ecosystems.

“The caenozoic era saw the evolution of complex mammalian societies.”

2. noun

the geologic time period from about 65 million to 2.6 million years ago, characterized by the emergence of mammals and the rise of modern ecosystems.

“The caenozoic era is often divided into several sub-periods.”