/ Dictionary / Index G gypsum board: Meaning and Definition of Find definitions for: gyp'sum board" Pronunciation: [key] wallboard composed primarily of gypsum and often used as sheathing. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. gypsum gypsum plaster Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language