apostlebirdDefinition of apostlebird noun a gregarious Australian bird of the mud-nester family, with grey, brown, and black plumage and a robust black bill. Struthidea cinerea, family Corcoracidae (or Grallinidae) Australian any of a number of other gregarious birds, especially babblers. Origin: early 20th century: named from the supposed habit of these birds of going about in flocks of twelve
