onco-

combining form

: tumor

oncology

Word History

Etymology

borrowed from Greek onko-, combining form of ónkos "mass, bulk," (Late Greek, "lump formed by a tumor"), of uncertain origin

Note: Traditionally ónkos has been treated as an o-grade nominal derivative of enenkeîn "to carry" (suppletive aorist of phérein), going back to a reduplicated aorist formation *h₁é-h₁n̥ḱ-e- from the verbal base *h₁nek- "carry." But given the certainty of this base, a derivative *h₁onḱ- would require assumption of a floating ablaut vowel. Perhaps more crucially, ónkos is nowhere attested in the meaning "burden," a necessary link if it is semantically derived from a verb "carry."