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.
      [1913 Webster]

            A free port, where nations . . . resorted with their
            goods and traded.                     --Arbuthnot.
      [1913 Webster]

   2. To buy and sell or exchange property in a single instance.
      [1913 Webster]

   3. To have dealings; to be concerned or associated; --
      usually followed by with.
      [1913 Webster]

            How did you dare to trade and traffic with Macbeth?
                                                  --Shak.
      [1913 Webster]

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.
      [1913 Webster]

   2. Frequented by traders. [R.] "They on the trading flood."
      --Milton.
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   3. Venal; corrupt; jobbing; as, a trading politician.
      [1913 Webster]

WordNet (r) 3.0 (2006):

trading
    n 1: buying or selling securities or commodities

Moby Thesaurus II by Grady Ward, 1.0:

65 Moby Thesaurus words for "trading":
   abalienation, agency, alienation, amortization, amortizement,
   assignation, assignment, backscratching, bargain and sale, barter,
   bartering, bequeathal, brokerage, business, buying and selling,
   cession, commercial, conferment, conferral, consignation,
   consignment, conveyance, conveyancing, dealing, deeding,
   deliverance, delivery, demise, disposal, disposition,
   doing business, enfeoffment, even trade, exchange, give-and-take,
   giving, horse trading, industrial, interchange, jobbing,
   lease and release, logrolling, mercantile, merchandising, merchant,
   pork barrel, retail, retailing, sale, settlement, settling,
   surrender, swap, swapping, switch, trade, trafficking, transfer,
   transference, transmission, transmittal, vesting,
   wheeling and dealing, wholesale, wholesaling