adj. Of, relating to, or being the epoch of geologic time from 5.3 to 2.6 million years ago, the most recent epoch of the Tertiary Period. It is characterized by the appearance of distinctly modern animals and by the expansion of grasslands. See Table at geologic time. n. The Pliocene Epoch. |
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.