onco-, onc-, onch-, oncho-, onci- +

(Greek: barb, hook)

Onchidium
A genus of slugs which live mostly on rocky seashores between tide levels.
Onchocerca
A genus of long, threadlike filarial nematodes of the family Onchocercidae.

They are found in subcutaneouis and connective tissue, or confined within tough, fibrous cysts. The most important species, Onchocerca volvulus is the cause of human onchocerciasis. Other species cause cutaneous diseases among domestic and wild herbivores.

Onchocerca gibsoni
A species found in cattle, sheep, and buffalo in India, southeast Asia, Egypt, and Australia. It forms hard nodules in the hides of cattle, thereby greatly reducing their commercial value.
Onchocerca lienalis
A species found in cattle and buffalo in various sites in connective tissue, including the cervical or tibiofemoral ligament and the spleen capsule. It is distributed throughout most of the world, but it is not common in the United States.
onchocerciasis, oncocerciasis
A disease caused by infection with filarial worms of the genus Onchocerca, primarily Onchocerca volvulus, transmitted by the bite of female blackflies of the genus Simulium. The disease is characterized by nodular swellings formed by fibrous cysts containing the worms.
onchocercoma
A subcutaneous nodule or lesion, usually situated near a bony prominence, that contains the adult worms in infections caused by Onchocerca species, especially Onchocerca vovulus.
onchodermatitis
The skin lesions in onchocerciasis, caused by migratory movements of the onchocerca microfilariae.
Oncidium
A large genus of tropical American epiphytic or terrestrial orchids, the butterfly orchids, that have flowers of great beauty; especially, in the commonly cultivated, West Indian Oncidium papilio and others grown for ornament.
oncomelania
A medically important genus of amphibious freshwater operculate snails of the family Hydrobiidae (subfamily Hydrobiinae; subclass Prosobranchiata). In the Orient, several subspecies of Oncomelania hupensis serve as intermediate hosts of the oriental blood fluke, Schistosoma japonicum.
oncomiracidium
A free swimming, ciliated larval stage of a fluke.
Oncorhynchus
A genus of salmon including the commercially important species of the North pacific and coastal streams of both American and Asiatic shores.

It is closely related to Salmo but differs in the increased number of anal rays, branchiostegals, pyloric caeca, and gill rakers.

oncosphere
The ciliated six-hooked larva of the tapeworm contained within the external embryonic envelope and armed with six hooks; it may be found in feces.