/ Dictionary / Index G geronto-: Meaning and Definition of Find definitions for: geronto- Pronunciation: [key] a combining form meaning “old age,” used in the formation of compound words: gerontology. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. gerontic gerontocracy Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language