/ Dictionary / Index F F region: Meaning and Definition of Find definitions for: F region Pronunciation: [key] the ionospheric region in which the F layer forms. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Frege Frei Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language