/ Dictionary / Index F flat arch: Meaning and Definition of Find definitions for: flat' arch' Pronunciation: [key] — Archit. Archit. an arch having a more or less flat intrados and extrados with voussoirs radiating from a center below the arch. See illus. underAlso called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. flat flat back Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language