/ Dictionary / Index M mastoiditis: Meaning and Definition of Find definitions for: mas•toid•i•tis Pronunciation: (mas"toi-dī'tis), [key] — n. Pathol. inflammation of the mastoid process. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mastoiditis (Thesaurus) mastoidectomy mastoid process Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language