Source : Webster's Revised Unabridged Dictionary (1913)

Unload \Un*load"\, v. t. [1st pref. un- + load.]
   1. To take the load from; to discharge of a load or cargo; to
      disburden; as, to unload a ship; to unload a beast.

   2. Hence, to relieve from anything onerous.

   3. To discharge or remove, as a load or a burden; as, to
      unload the cargo of a vessel.

   4. To draw the charge from; as, to unload a gun.

   5. To sell in large quantities, as stock; to get rid of.
      [Brokers' Cant, U. S.]

Unload \Un*load"\, v. i.
   To perform the act of unloading anything; as, let unload now.

Source : WordNet®

unload
     v 1: leave or unload, especially of passengers or cargo; [syn: {drop},
           {set down}, {put down}, {discharge}]
     2: take the load off (a container or vehicle); "unload the
        truck"; "offload the van" [syn: {offload}]