/ Dictionary / Index C costotomy: Meaning and Definition of Find definitions for: cos•tot•o•my Pronunciation: (ko-stot'u-mē), [key] — pl. -mies. incision of a rib. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. costotome cost overrun 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