The term 'Large Flightless Bird' can refer to four different species: the EMU (3 letters), CASSOWARY (9 letters), OSTRICH (7 letters), and RHEA (4 letters). The EMU is a large, flightless bird native to Australia, while the CASSOWARY is a large, flightless bird native to New Guinea and northeastern Australia. The OSTRICH is the largest living bird in the world and is native to Africa, while the RHEA is a large, flightless bird native to South America. All four of these species are unable to fly due to their size and lack of wings.