The Collaborative International Dictionary of English v.0.48:

Briony \Bri"o*ny\, n.
   See Bryony. --Tennyson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

briony
    n 1: a vine of the genus Bryonia having large leaves and small
         flowers and yielding acrid juice with emetic and purgative
         properties [syn: bryony, briony]