/ Dictionary / Index F flyby: Meaning and Definition of Find definitions for: fly•by Pronunciation: (flī'bī"), [key] — pl. -bys. the flight of a spacecraft close enough to a celestial object, as a planet, to gather scientific data. Also calledflypast.a low-altitude flight of an aircraft for the benefit of ground observers. flyover (def. 1). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. flybridge fly-by-night Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language