The Collaborative International Dictionary of English v.0.48:

Trade \Trade\, v. i. [imp. & p. p. Traded; p. pr. & vb. n.
   Trading.]
   1. To barter, or to buy and sell; to be engaged in the
      exchange, purchase, or sale of goods, wares, merchandise,
      or anything else; to traffic; to bargain; to carry on
      commerce as a business.
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            A free port, where nations . . . resorted with their
            goods and traded.                     --Arbuthnot.
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   2. To buy and sell or exchange property in a single instance.
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   3. To have dealings; to be concerned or associated; --
      usually followed by with.
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            How did you dare to trade and traffic with Macbeth?
                                                  --Shak.
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The Collaborative International Dictionary of English v.0.48:

Trading \Trad"ing\, a.
   1. Carrying on trade or commerce; engaged in trade; as, a
      trading company.
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   2. Frequented by traders. [R.] "They on the trading flood."
      --Milton.
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   3. Venal; corrupt; jobbing; as, a trading politician.
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WordNet (r) 3.0 (2006):

trading
    n 1: buying or selling securities or commodities