Eocene

[ ee-uh-seen ]

adjective

noting or pertaining to an epoch of the Tertiary Period, occurring from 55 to 40 million years ago and characterized by the advent of the modern mammalian orders.

noun

the Eocene Epoch or Series.

Origin of Eocene

First recorded in 1825–35; eo- + -cene

Other words from Eocene

post-E·o·cene, adjective

Words Nearby Eocene

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use Eocene in a sentence

The fourth area displays a very different succession of Eocene strata, and one of extreme interest.
The Principles of Stratigraphical Geology | J. E. Marr
This uplift imprisoned an enormous Eocene lake that occupied much of what is now the Colorado River basin.
Your National Parks | Enos A. Mills
The Middle Eocene is represented by the well-known “Calcaire grossier,” about 90 ft. thick.
Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 6 | Various
The late Eocene flora of Europe was very similar to its descendant in modern Australasia.
Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 6 | Various
Marls and limestones with fossils of an Eocene facies overlie the Cretaceous rocks on the Gabun.
Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 1 "Franciscans" to "French Language" | Various

British Dictionary definitions for Eocene

Eocene

/ (ˈiːəʊˌsiːn) /

adjective

of, denoting, or formed in the second epoch of the Tertiary period, which lasted for 20 000 000 years, during which hooved mammals appeared

noun

the Eocene the Eocene epoch or rock series

Origin of Eocene

C19: from eo- + -cene

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for Eocene

Eocene

[ ē′ə-sēn′ ]

The second epoch of the Tertiary Period, from about 58 to 37 million years ago. During the earliest part of this epoch, land connections existed between Antarctica and Australia, between Europe and North America, and between North America and Asia, and the climate was warm. The land connection between Antarctica and Australia disappeared in the mid-Eocene and early Oligocene, resulting in a change in the predominant oceanic currents and a cooler climate. With this change, the average size of mammals changed from less than 10 kg (22 lbs) to more than 10 kg. The Himalayas also formed during the Eocene, and most modern orders of mammals appeared. See Chart at geologic time.

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