chemosphere: Meaning and Definition of

che•mo•sphere

Pronunciation: (kē'mu-sfēr", kem'u-), [key]
— n.
  1. the region of the atmosphere most characterized by chemical, esp. photochemical, activity, starting in the stratosphere and including the mesosphere and perhaps part of the thermosphere.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.