/ Dictionary / Index G grotto: Meaning and Definition of Find definitions for: grot•to Pronunciation: (grot'ō), [key] — pl. -toes, -tos. a cave or cavern. an artificial cavernlike recess or structure. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: grotto (Thesaurus) Groton grotty 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