What does the prefix "Onc-" refer to?

The prefix "Onc-" originates from the Greek word "onkos," which means mass or tumor. In medical terminology, it specifically relates to tumors in the context of oncology, the branch of medicine that deals with the diagnosis and treatment of cancer. Thus, when you see the prefix "Onc-," it typically pertains to growths, whether benign or malignant, making "tumor" the correct association in this case. This is important in understanding various medical terms related to cancer, like "oncologist" (a doctor who specializes in tumors and cancer treatment) and "oncology" (the study of tumors).