The Collaborative International Dictionary of English v.0.48:

Epiornis \Ep`i*or"nis\, n. [NL.: cf. F. ['e]piornis. See
   [AE]pyornis.] (Zo["o]l.)
   One of the gigantic ostrichlike birds of the genus
   [AE]piornis, only recently extinct. Its remains have been
   found in Madagascar. [Written also [AE]pyornis.]
   [1913 Webster]