Ostrich, e.g.

• Cassowary, for one
• Emus
• Rheas
• Emu or Rhea
• Rhea, e.g
• Rhea or ostrich

Wiktionary Word definitions in Wiktionary
n. A bird of the order of Struthioniformes, a diverse group of large running, flightless birds, mostly extinct, but including the cassowary, elephant bird, emu, kiwi, moa, ostrich, rhea and tinamou

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Ratite \Rat"ite\ (r[a^]t"[imac]t), a. (Zo["o]l.) Of or pertaining to the Ratit[ae]. -- n. One of the Ratit[ae].

WordNet Word definitions in WordNet
n. flightless birds having flat breastbones lacking a keel for attachment of flight muscles: ostriches; cassowaries; emus; moas; rheas; kiwis; elephant birds [syn: ratite bird , flightless bird ] [ant: carinate ]

Wikipedia Word definitions in Wikipedia
A ratite is any of a diverse group of large, flightless birds of the infraclass Palaeognathae . The systematics involved have been in flux. Some sources state that ratites include all the flightless birds of the Palaeognathae; previously, all these birds ...