What does the prefix "onco" mean?

The prefix "onco" is derived from the Greek word "onkos," which means tumor or mass. In the context of oncology, which is the branch of medicine that deals with the diagnosis and treatment of cancer, "onco" specifically refers to tumors associated with cancerous growths. Therefore, this prefix is commonly used in medical terminology relating to cancer, such as in the words "oncology," "oncologist," and "oncolysis." Understanding this prefix is vital for grasping the fundamental concepts in cancer care and treatment, as it directly relates to the nature of cancer itself, which involves the presence of tumors.