The Collaborative International Dictionary of English v.0.48:

Exportation \Ex`por*ta"tion\, n. [L. exportatio: cf. F.
   exporation.]
   1. The act of exporting; the act of conveying or sending
      commodities abroad or to another country, in the course of
      commerce.
      [1913 Webster]

   2. Commodity exported; an export.
      [1913 Webster]

   3. The act of carrying out. [R.] --Bourne.
      [1913 Webster]

WordNet (r) 3.0 (2006):

exportation
    n 1: commodities (goods or services) sold to a foreign country
         [syn: export, exportation] [ant: import,
         importation]
    2: the commercial activity of selling and shipping goods to a
       foreign country [syn: exporting, exportation]

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

EXPORTATION, commercial law. The act of sending goods and merchandise from
one country to another. 2 Mann. & Gran. 155; 3 Mann. & Gran. 959.
     2. In order to preserve equality among the states, in their commercial
relations, the constitution provides that "no tax or duty shall be laid on
articles exported from any state." Art. 1, s. 9. And to prevent a pernicious
interference with the commerce of the nation, the 10th section of the 1st
article of the constitution contains the following prohibition: "No state
shall, without the consent of congress, lay any imposts or duties on imports
or exports, except what may be absolutely necessary for executing its
inspection laws; and the net produce of all duties and imposts, laid by any
state on imports or exports, shall be for the use of the treasury of the
United States; and all such laws shall be subject to the revision and
control of the congress." Vide 12 Wheat. 419; and the article Importation.