Origin of ionosphere; from ion + -o- + sphere
iono- + -sphere
ionosphere - Computer Definition
Four regions of the Earth's outer atmosphere, beginning at an altitude of approximately 55 kilometers (34 miles), ionized by solar radiation.The ionosphere contains high concentrations of ions and free electrons, and can serve to reflect certain radio signals back to Earth, depending on their frequency and angle of incidence. Long-range radio communications depend on this skywave propagation, or atmospheric skip. See also angle of incidence, frequency, and skywave.