Paleocene

[ pey-lee-uh-seen or, especially British, pal-ee- ]

adjective
  1. noting or pertaining to an epoch of the Tertiary Period, from 65 to 55 million years ago, and characterized by a proliferation of mammals.

noun
  1. the Paleocene Epoch or Series.

Origin of Paleocene

1
First recorded in 1875–80; paleo- + -cene

Words Nearby Paleocene

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

How to use Paleocene in a sentence

Scientific definitions for Paleocene

Paleocene

[ lē-ə-sēn′ ]


  1. The earliest epoch of the Tertiary Period, from about 65 to 58 million years ago. During this time, the Rocky Mountains formed and sea levels dropped, exposing dry land in North America, Australia, and Africa. Many new types of small mammals evolved and filled the niches left empty after the extinctions that ended the Cretaceous Period. Soft-bodied squid replaced the ammonites as the dominant form of mollusk. See Chart at geologic time.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.