Any one of three species of South American ostriches of the genera
Rhea and
Pterocnemia, especially the smallest,
Pterocnemia pennata (formerly
Rhea Americana), called also the
common rhea. They are tall fast-running flightless birds similar to ostriches but three-toed, found from Peru to the Straits of Magellan. See
Rhea. [
1913 Webster]