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]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

CONSIGNOR, contracts. One who makes a consignment to another.
     2. When goods are consigned to be sold on commission, and the property
remains in the consignor; or when goods have been consigned upon a credit,
and the consignee has become a bankrupt or failed, the consignor has a right
to stop them in transitu. (q.v.) Abbot on Sh. p. 3, c.
     3. The consignor is generally liable for the freight or the hire for
the carriage of goods. 1 T. R. 659.