/ Dictionary / Index M mastoidectomy: Meaning and Definition of Find definitions for: mas•toid•ec•to•my Pronunciation: (mas"toi-dek'tu-mē), [key] — pl. -mies. the removal of part of a mastoid process, usually for draining an infection. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mastoidectomy (Thesaurus) mastoid mastoiditis Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language