Eocene

[ ee-uh-seen ]

adjective

1. 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

1. the Eocene Epoch or Series.

Eocene

/ ˈiːəʊˌsiːn /

adjective

1. 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

1. the Eocene
   the Eocene epoch or rock series

Eocene

/ ē′ə-sēn′ /

1. 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.
2. See Chart at geologic time

Other Words From

• post-Eo·cene adjective

Word History and Origins

Origin of Eocene¹

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

Word History and Origins

Origin of Eocene¹

C19: from eo- + -cene

Example Sentences

Indeed, from the larger perspective of Earth’s planetary history, Antarctica was green for a large chunk of time, specifically during the period prior to the Eocene Epoch 56 million years ago.

From Salon

All but the most specialist sea plankton moved to higher latitudes during the Early Eocene Climatic Optimum, an interval of sustained high global temperatures equivalent to worst case global warming scenarios.

From Science Daily

Washington in the Eocene looked different from today, with a coastline well east of where Seattle sits today and a chain of volcanic islands dotting the horizon offshore.

From Science Daily

The KU researchers said their discovery is not only exciting in terms of discovering a new primate species from late Eocene China -- but also in settling the origin story of Ekgmowechashala.

From Science Daily

Bones of these large grazing animals found in Oregon’s John Day area and in southern British Columbia confirm that titanotheres were in this region in the early Eocene.

From Seattle Times