/ Dictionary / Index G gypsum plaster: Meaning and Definition of Find definitions for: gyp'sum plas"ter Pronunciation: [key] plaster made primarily of gypsum. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. gypsum board Gypsy 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