/ Dictionary / Index S sponge iron: Meaning and Definition of Find definitions for: sponge' i"ron Pronunciation: [key] finely divided, porous iron, reduced from an oxide at a temperature below the melting point. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. spongefly sponger Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language