Definitions for oncogeneˈɒŋ kəˌdʒin
Random House Webster's College Dictionary
any gene that is a causative factor in the initiation of cancerous growth.
Origin of oncogene:
oncogene, transforming gene(noun)
a gene that disposes normal cells to change into cancerous tumor cells
Any gene that contributes to the conversion of a normal cell into a cancerous cell when mutated or expressed at high levels.