roadrunner \ˈ ̷ ̷ˌ ̷ ̷ ̷ ̷\noun 1.: a bird (Geococcyx californianus) of largely terrestrial habits that resembles a cuckoo and is noted for running with great speed and that ranges from California to Mexico and eastward to Texas — called also chaparral bird 2.: a Mexican bird (Geococcyx velox) similar and closely related to the roadrunner