roadrunner UK /ˈɹəʊdˌɹʌnə/US /ˈɹoʊdˌɹʌnɚ/ noun1 •Either of two species of fast-running bird in the genus Geococcyx of the cuckoo family native to North and Central America, the lesser roadrunner (Geococcyx velox) and, especially, the greater roadrunner (Geococcyx californianus). formsroadrunners