Definitions for ecosphereˈɛk oʊˌsfɪər, ˈi koʊ-
Random House Webster's College Dictionary
ec•o•sphereˈɛk oʊˌsfɪər, ˈi koʊ-(n.)
the part of the atmosphere, from sea level to about 13,000 ft. (4000 m) above, in which it is possible to breathe normally without aid.
Ref: biosphere .
Origin of ecosphere:
The portion of the atmosphere from sea-level to about 4000 meters in which it is possible to breathe without technological assistance.