Ionosphere

noun

noun ·4 syllables ·Uncommon ·Advanced level

Definitions

Noun
  1. 1
    The part of the Earth's atmosphere beginning at an altitude of about 50 kilometers (31 miles) and extending outward 500 kilometers (310 miles) or more.

    "Dave frowned as he tried to answer. "Well, I suppose the atmosphere is oxygen and nitrogen, mostly; then there's the ionosphere and the ozone layer. As I remember, the color of the sky is due to the scattering of light—light rays being diffracted in the air.""

  2. 2
    the outer region of the Earth's atmosphere; contains a high concentration of free electrons wordnet
  3. 3
    The similar region of the atmosphere of another planet.

Synonyms

All synonyms
aerospaceaerosphereairair holeair pocketair space

Example

More examples

"The five-minute trip will be to study a global electrical current called the dynamo that sweeps through the ionosphere."

Etymology

From iono- + -sphere.

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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.