1. (noun) flightless birds having flat breastbones lacking a keel for attachment of flight muscles: ostriches; cassowaries; emus; moas; rheas; kiwis; elephant birds

• flightless bird
• ratite

1. (noun) flightless birds having flat breastbones lacking a keel for attachment of flight muscles: ostriches; cassowaries; emus; moas; rheas; kiwis; elephant birds

• aepyornis
• elephant bird
• apteryx
• kiwi
• cassowary
• dromaius novaehollandiae
• emu
• emu novaehollandiae
• moa
• nandu
• pterocnemia pennata
• rhea
• ostrich
• struthio camelus
• rhea
• rhea americana

1. (noun) flightless birds having flat breastbones lacking a keel for attachment of flight muscles: ostriches; cassowaries; emus; moas; rheas; kiwis; elephant birds

• bird

1. (noun) flightless birds having flat breastbones lacking a keel for attachment of flight muscles: ostriches; cassowaries; emus; moas; rheas; kiwis; elephant birds

• carinate
• carinate bird
• flying bird