megafauna definition by American Heritage Dictionary
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
noun (used with a sing. or pl. verb)
Large or relatively large animals, as of a particular region or period, considered as a group.
- megˈa·fauˌnal adjective
megafauna - Science Definition
Large or relatively large animals of a particular place or time period. Saber-toothed tigers and mastodons belong to the extinct megafauna of the Oligocene and Pleistocene Epochs.