/ Dictionary / Index H hardhead sponge: Meaning and Definition of Find definitions for: hard'head sponge' Pronunciation: [key] any of several commercial sponges, as Spongia officinalis dura, of the West Indies and Central America, having a harsh, fibrous, resilient skeleton. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. hardheaded hardhearted Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language