Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
any of a series of biogeographic zones into which a continent, region, etc. is divided both by latitude and altitude on the basis of the characteristic animal and plant life in a zone
Used by arrangement with John Wiley & Sons, Inc.
nounThe 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.
A geographic region or area defined by its characteristic life forms.