/ Dictionary / Index F flu: Meaning and Definition of Find definitions for: flu Pronunciation: (fl), [key] — n. influenza. a specific variety of influenza, usually named for its point of dissemination or its animal vector: Hong Kong flu; swine flu. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: flu (Thesaurus) FLRA flub Related Content Daily Word Quiz: morose Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language