Sentence:  Both cassowaries and <WSD>emus</WSD> are large, flightless, cursorial birds with diminutive wings. ... <WSD>Emus</WSD>, the world's second largest living birds, live in Australia and are the only extant member of the genus "Dromaius". 
Meaning of the word marked with <WSD> tags:  A large flightless bird native to Australia, "Dromaius novaehollandiae". (from 18th c.)