/ Dictionary / Index G grandsire: Meaning and Definition of Find definitions for: grand•sire Pronunciation: (grand'sīr"), [key] — n. a grandfather. a forefather. an aged man. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. grand serjeanty grand slam Related Content Daily Word Quiz: pristine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language