‖n. pl. [ NL. See Struthio. ] (Zool.) (a) A division, or order, of birds, including only the African ostriches. (b) In a wider sense, an extensive group of birds including the ostriches, cassowaries, emus, moas, and allied birds incapable of flight. In this sense it is equivalent to Ratitae, or Dromaeognathae. [ 1913 Webster ]