Definitions
There is 1 meaning of the phrase
F Region.
F Region - as a noun
The highest region of the ionosphere (from 90 to 600 miles up) which contains the highest concentration of free electrons and is most useful for long-range radio transmission
Synonyms (Exact Relations)
appleton layerf layerExample Sentences
"The f region of the ionosphere is responsible for reflecting radio waves back to the Earth."