stratosphere

/ˌstrædəˈsfɪər/

Other forms: stratospheres

When an astronomer talks about the stratosphere, she means the second layer of Earth's atmosphere, about six miles above the surface of our planet.

The atmosphere around Earth is divided into three sections — first, the troposphere, next the stratosphere, and finally the outer layer, the mesosphere. It sounds like outer space, but actually large commercial airplanes often fly at altitudes that reach the stratosphere. People also use the word stratosphere in a figurative way to mean "really high," as when a car salesman brags, "Our sales this month have skyrocketed into the stratosphere!"

Definitions of stratosphere

1. noun

   the atmospheric layer between the troposphere and the mesosphere
   type of:

   layer

   a relatively thin sheetlike expanse or region lying over or under another