All the living matter on or in the earth, the oceans and seas, and the atmosphere. The area of the planet in which life is found to occur.
Literally, the part of the earth that supports life; more broadly, a large community of life-forms sharing a similar environment, such as a rain forest or prairie grassland.
The sphere of living organisms including the land, water, and air.
The parts of earth’s land, water, and atmosphere in which living organisms can exist.