Definition of ionosphere noun from the Oxford Advanced Learner's Dictionary



BrE BrE//aɪˈɒnəsfɪə(r)//
; NAmE NAmE//aɪˈɑːnəsfɪr//
the ionosphere [singular] The Earth and the atmosphere
jump to other results
a layer of the earth’s atmosphere between about 80 and 1 000 kilometres above the surface of the earth, that reflects radio waves around the earth compare stratosphere See related entries: The Earth and the atmosphere
See the Oxford Advanced American Dictionary entry: ionosphere