from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Of or belonging to the geologic time, rock series, or sedimentary deposits of the third epoch of the Tertiary Period, characterized by futher development of modern mammalian fauna, including the rise of the true carnivores and their gradual replacement of the creodonts. See Table at geologic time.
- n. The Oligocene Epoch or its system of deposits.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Of a geologic epoch within the Paleogene period from about 34 to 23 million years ago; marked by the rapid evolution in a warm climate.
- proper n. The Oligocene epoch.
from the GNU version of the Collaborative International Dictionary of English
- adj. Of, pertaining to, or designating, certain strata which occupy an intermediate position between the Eocene and Miocene periods.
from The Century Dictionary and Cyclopedia
- In geology, a division of the Tertiary series, including groups formerly classed in part as Upper Eocene and in part as Lower Miocene.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. from 40 million to 25 million years ago; appearance of sabertoothed cats
From oligo- + -cene (Wiktionary)