the highest of the radio-reflective ionospheric layers, beginning at an altitude of about 80 miles (130 km) and consisting of two parts, the lower part (F layer) being detectable in the daytime only, the higher (F layer or Appleton layer) being constant and constituting the ionospheric layer most favorable for long-range radio communication.
What’s The Origin Of The F-word?It's one of the most versatile words in the English language, but where did the F-word really come from? Originally, the naughtiest of naughty words was actually quite an acceptable word, though no English speaker would say that today.
Origin of F layer
First recorded in 1925–30
Definition for f layer (2 of 3)
[ ef wuhn ]
/ ˈɛf ˈwʌn /
Definition for f layer (3 of 3)
[ ef too ]
/ ˈɛf ˈtu /
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Science definitions for f layer
See F region.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.