The Collaborative International Dictionary of English v.0.48:

Transshipment \Trans*ship"ment\, n.
   The act of transshipping, or transferring, as goods, from one
   ship or conveyance to another. [Written also transhipment.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

transshipment
    n 1: the transfer from one conveyance to another for shipment

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "transshipment":
   air express, airfreight, airlift, asportation, bearing, carriage,
   carry, carrying, cartage, conveyance, drayage, expressage,
   ferriage, freight, freightage, haulage, hauling, lighterage,
   lugging, packing, portage, porterage, railway express, shipment,
   shipping, telpherage, toting, transport, transportation, truckage,
   waft, waftage, wagonage