ionosphere

 
Pronunciation: /ʌɪˈɒnəsfɪə/

noun

  • the layer of the earth’s atmosphere which contains a high concentration of ions and free electrons and is able to reflect radio waves. It lies above the mesosphere and extends from about 80 to 1,000 km above the earth’s surface.

Derivatives

ionospheric

Pronunciation: /-ˈsfɛrɪk/
adjective