The Collaborative International Dictionary of English v.0.48:

Consignor \Con*sign"or\ (? or ?; 277), n.
   One who consigns something to another; -- opposed to
   consignee. [Written also consigner.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

consignor
    n 1: the person who delivers over or commits merchandise [syn:
         consigner, consignor]