word-forming element meaning "bulk, mass," used from 19c., especially in medical use, "tumor," from Latinized form of Greek ogkos (pronounced "onkos") "bulk, size, mass, weight, swelling," in Modern Greek "tumor," a word of uncertain origin.
Entries linking to onco-
oncogene n.
"gene which can transform a normal cell into a tumor cell," 1969, from onco- "tumor" + -gene, from root of Greek gignere (perfective genui) "to beget, produce" (from PIE root *gene- "give birth, beget"). Related: Oncogenesis "formation or production of tumors" (1932); oncogenic (1949).
oncology n.
"the scientific study of tumors," 1857, coined in English from onco- "tumor" + -logy "science or study of." Related: Oncologist; oncological.