The Collaborative International Dictionary of English v.0.48:

Celastrus \Celastrus\ n.
   the type genus of the Celastraceae, comprising the plants
   called climbing bittersweet; bittersweet and shrubby
   bittersweet; they are woody vines and shrubs native chiefly
   to Asia and Australia, bearing yellow to orange capsules
   which open to expose red-coated seeds. See also
   bittersweet[3b].

   Syn: genus Celastrus.
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

Celastrus
    n 1: genus of woody vines and erect shrubs (type genus of the
         Celastraceae) that is native chiefly to Asia and Australia:
         includes bittersweet [syn: Celastrus, genus Celastrus]