/ Dictionary / Index G granduncle: Meaning and Definition of Find definitions for: grand•un•cle Pronunciation: (grand'ung"kul), [key] — n. an uncle of one's father or mother; a great-uncle. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: granduncle (Thesaurus) Grand Turk grand unification theory 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