The Collaborative International Dictionary of English v.0.48:

Vetch \Vetch\ (v[e^]ch), n. [Also fitch; OE. ficche, feche, for
   veche, OF. veche, vecce, vesche, vesce, F. vesce, fr. L.
   vicia.] (Bot.)
   Any leguminous plant of the genus Vicia, some species of
   which are valuable for fodder. The common species is Vicia
   sativa.
   [1913 Webster]

   Note: The name is also applied to many other leguminous
         plants of different genera; as the chichling vetch, of
         the genus Lathyrus; the horse vetch, of the genus
         Hippocrepis; the kidney vetch (Anthyllis
         vulneraria); the milk vetch, of the genus
         Astragalus; the licorice vetch, or wild licorice
         (Abrus precatorius).
         [1913 Webster]

WordNet (r) 3.0 (2006):

vetch
    n 1: any of various climbing plants of the genus Vicia having
         pinnately compound leaves that terminate in tendrils and
         small variously colored flowers; includes valuable forage
         and soil-building plants