/ Dictionary / Index C costotome: Meaning and Definition of Find definitions for: cos•to•tome Pronunciation: (kos'tu-tōm"), [key] — n. Surg. an instrument, as shears or a knife, for incising or dividing a rib, as in costotomy. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. cost-of-living index costotomy Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language