/ Dictionary / Index F flux density: Meaning and Definition of Find definitions for: flux' den"sity Pronunciation: [key] — Physics. Physics. the magnetic, radiant, or electric flux per unit of cross-sectional area. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. flux flux gate Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language