Definition of Ratitae
in some classifications
: a superordinal group of birds comprising forms with small or rudimentary wings, no pygostyle, and no keel to the breastbone that are nonetheless evidently descended from birds with the power of flight, including the ostriches, rheas, cassowaries and emus, elephant birds, moas, and kiwis, and usually constituting a primary subdivision of the subclass Neornithes
