eocene

Pronunciation key ( ē′ə-sēn )

E•o•cene

adj.

[eo- + Gr. kainos new].

1. The earliest epoch of the Tertiary Period which occurred during the Cenozoic Era, when mammals became the dominant group of animals on the planet.
2. Rocks belonging to the epoch.

References

Webster's New World Dictionary of the American Language (College Edition) ©1955