The number and variety of organisms found within a specified geographic region.
The variability among living organisms on the earth, including the variability within and between species and within and between ecosystems.
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.