Ionosphere (noun)

1. The uppermost layer of the Earth's atmosphere, between about 50 and 600 km above the Earth's surface, where the atmosphere is ionized by solar radiation.
2. The region of the Earth's atmosphere in which ions and free electrons are present.

Origin:

Early 20th century: from ion + -osphere, on the pattern of atmosphere.

Examples:

1. The ionosphere reflects radio waves, allowing long-distance communication.
2. Solar flares can disrupt the ionosphere, causing communication problems.
3. The ionosphere helps protect the Earth from harmful solar radiation.
4. The study of the ionosphere is important for understanding space weather.
5. Satellites use the ionosphere for navigation and to study atmospheric processes.