Breadcrumb Home > Dictionary > Index O onchocerciasis: Meaning and Definition of Find definitions for: on•cho•cer•ci•a•sis Pronunciation: (ong"kō-sur-kī'u-sis), [key] — n. Pathol. an infestation with filarial worms of the genus Onchocerca, common in tropical America and Africa, transmitted by black flies, and characterized by nodules under the skin, an itchy rash, eye lesions, and in severe cases, elephantiasis. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: onchocerciasis (Thesaurus) once-over-lightly oncidium ✖ Related Content Daily Word Quiz: musth Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language