a region of the earth's atmosphere, extending from about 60 kilometres to 1000 km above the earth's surface, in which there is a high concentration of free electrons formed as a result of ionizing radiation entering the atmosphere from space
See also D region, E region, F region
Derived forms
ionospheric (aɪˌɒnəˈsfɛrɪk)
adjective
ionosphere in American English
(aɪˈɑnəˌsfɪr)
noun
the outer part of the earth's atmosphere, beginning at an altitude of c. 55 km (c. 34 mi) and extending to the highest parts of the atmosphere: it contains several regionsthat consist of a series of constantly changing layers characterized by an appreciable electron and ion content