noun

• (geology, obsolete) Collectively, those layers of the Earth’s crust which primarily comprise stratified deposits.
  "So great is the part played by stratified deposits in the structure of the earth’s crust that we might be tempted to speak of the stratosphere of the earth in contradistinction to the scoriosphere of the moon."
• (meteorology) The region of the uppermost atmosphere where temperature increases along with the altitude due to the absorption of solar ultraviolet radiation by ozone. The stratosphere extends from the tropopause (10–15 kilometers) to approximately 50 kilometers, where it is succeeded by the mesosphere.
  "Variation in height of the stratosphere (isothermal layer)."