/ Dictionary / Index G gaylussite: Meaning and Definition of Find definitions for: gay•lus•site Pronunciation: (gā'lu-sīt"), [key] — n. a rare mineral, hydrated carbonate of sodium and calcium. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Gay-Lussac's law gayly 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