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Definition of "ionosphere" [ionosphere]

  • A region of the earth's atmosphere where ionization caused by incoming solar radiation affects the transmission of radio waves. It extends from a height of 70 kilometers (43 miles) to 400 kilometers (250 miles) above the surface. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Use "ionosphere" in a sentence
  • "Nobel Prizeman himself, who gave me the warmest encouragement and help when I began to work on the ionosphere, is not alive today to let me hear his own words of approval."
  • "We have a diurnal pattern of a distribution of earthquakes controlled by a current in the ionosphere, which is controlled by the activity on the sun."
  • "CFCs are also safe, inert and nonpoisonous-until they reach the ionosphere, that is."