/ Dictionary / Index O oncology: Meaning and Definition of Find definitions for: on•col•o•gy Pronunciation: (ong-kol'u-jē), [key] — n. the branch of medical science dealing with tumors, including the origin, development, diagnosis, and treatment of malignant neoplasms. the study of cancer. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: oncology (Thesaurus) oncogenicity oncoming Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language