/ Dictionary / Index F fill-up: Meaning and Definition of Find definitions for: fill-up Pronunciation: (fil'up"), [key] — n. an act or instance of filling up, as a tank with fuel. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: fill-up (Thesaurus) Fillmore filly Related Content Daily Word Quiz: crutiny Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language