The Collaborative International Dictionary of English v.0.48:

Dispatch \Dis*patch"\, n. [Cf. OF. despeche, F. d['e]p[^e]che.
   See Dispatch, v. t.] [Written also despatch.]
   1. The act of sending a message or messenger in haste or on
      important business.
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   2. Any sending away; dismissal; riddance.
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            To the utter dispatch of all their most beloved
            comforts.                             --Milton.
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   3. The finishing up of a business; speedy performance, as of
      business; prompt execution; diligence; haste.
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            Serious business, craving quick dispatch. --Shak.
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            To carry his scythe . . . with a sufficient dispatch
            through a sufficient space.           --Paley.
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   4. A message dispatched or sent with speed; especially, an
      important official letter sent from one public officer to
      another; -- often used in the plural; as, a messenger has
      arrived with dispatches for the American minister; naval
      or military dispatches.
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   5. A message transmitted by telegraph. [Modern]
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   Dispatch boat, a swift vessel for conveying dispatches; an
      advice boat.

   Dispatch box, a box for carrying dispatches; a box for
      papers and other conveniences when traveling.

   Syn: Haste; hurry; promptness; celerity; speed. See Haste.
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WordNet (r) 3.0 (2006):

dispatch box
    n 1: case consisting of an oblong container (usually having a
         lock) for carrying dispatches or other valuables [syn:
         dispatch case, dispatch box]