from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The part of the earth and its atmosphere in which living organisms exist or that is capable of supporting life.
- n. The living organisms and their environment composing the biosphere.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. the part of the Earth and its atmosphere capable of supporting life
- n. the totality of living organisms and their environment
from The Century Dictionary and Cyclopedia
- n. The sum of the living things on the earth considered as a stratum in contrast with the atmosphere and the lithosphere.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the regions of the surface and atmosphere of the Earth (or other planet) where living organisms exist
bio- + sphere (Wiktionary)