The Collaborative International Dictionary of English v.0.48:

Syncarpous \Syn*car"pous\, a. [Pref. syn- + Gr. ? a fruit.]
   (Bot.)
   Composed of several carpels consolidated into one ovary.
   [1913 Webster]

WordNet (r) 3.0 (2006):

syncarpous
    adj 1: (of ovaries of flowering plants) consisting of united
           carpels [ant: apocarpous]