/ Dictionary / Index P periodontium: Meaning and Definition of Find definitions for: per•i•o•don•tium Pronunciation: (per"ē-u-don'shum, -shē-um), [key] — pl. -tia the bone, connective tissue, and gum surrounding and supporting a tooth. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. periodontitis periodontology Related Content Daily Word Quiz: philately Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language