F REGION as NOUN

1. Meaning
   • the highest region of the ionosphere (from 90 to 600 miles up) that contains the highest concentration of free electrons and is most useful for long-range radio transmission
   Synonym(s)
   • Appleton layer (what does Appleton layer mean?)
   • F layer (what does F layer mean?)
   Hypernyms(s) F region is a kind of… Example: animal is a hypernym of mammal, plant is a hypernym of flower
   • region (what does region mean?)
   • part (what does part mean?)