411 REFERENCE · Wiktionary
F region
Reference material by Wiktionary contributors. This retains its source identity and is not 411 news reporting.
English
Alternative forms
en F-region
Etymology
en
Proper noun
F region 1
The middle layer of the ionosphere, located 90 km (56 mi) to 150 km (93 mi) above the surface of the Earth.
Synonyms
Appleton layer
Appleton-Barnett layer
F layer
Further reading
en Atmosphere