The Collaborative International Dictionary of English v.0.48:

Avena \A*ve"na\, n. [L.] (Bot.)
   A genus of grasses, including the common oat (Avena
   sativa); the oat grasses.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Avena
    n 1: oats [syn: Avena, genus Avena]