backcrossEnglishOxford Dictionary of Englishbackcross /ˈbakkrɒs / Genetics ▸ verb [with object] cross (a hybrid) with one of its parents or an organism with the same genetic characteristics as one of the parents: (backcrossed as adjective) after five generations the backcrossed dogs were indistinguishable from pure-bred Dalmatians. ▸ noun an instance or result of backcrossing.