Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “the ionosphere”

the ionosphere

noun [S]     /aɪˈɒn.əˌsfɪər/ US  /-ˈɑːn.əˌsfɪr/ specialized
part of the Earth's atmosphere, from about 60 kilometres to about 1,000 kilometres above the surface, in which there are many ions → Compare the exosphere, the mesosphere, the stratosphere, the thermosphere, the troposphereThe Earth and outer space - general words ionospheric     /aɪˌɒ.nəˈsfer.ɪk/ US  /-ˌɑːn.ə-/ adjective The Earth and outer space - general words
(Definition of the ionosphere noun from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
Focus on the pronunciation of the ionosphere

Translations of “the ionosphere”

Word of the Day

well in (with)

to have a good relationship with someone in which they like you and from which you get an advantage

Word of the Day

Blog

Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More