outcross Syllabification: (out·cross)Definition of outcross verb Pronunciation: /ˌoutˈkrôs, -ˈkräs/ [with object] breed (an animal or plant) with one not closely related. noun Pronunciation: /ˈoutˌkrôs, -ˈkräs/ an animal or plant produced as the result of outcrossing. outcross in other Oxford dictionaries Definition of outcross in the British & World English dictionary