/ Dictionary / Index O oncogene: Meaning and Definition of Find definitions for: on•co•gene Pronunciation: (ong'ku-jēn"), [key] — n. Genetics. any gene that is a causative factor in the initiation of cancerous growth. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: oncogene (Thesaurus) onco- oncogenesis Related Content Daily Word Quiz: agitated Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language