Source : Webster's Revised Unabridged Dictionary (1913)

Traffic \Traf"fic\, n. [Cf. F. trafic, It. traffico, Sp.
   tr['a]fico, tr['a]fago, Pg. tr['a]fego, LL. traficum,
   trafica. See {Traffic}, v.]
   1. Commerce, either by barter or by buying and selling;
      interchange of goods and commodities; trade.

            A merchant of great traffic through the world.
                                                  --Shak.

            The traffic in honors, places, and pardons.
                                                  --Macaulay.

   Note: This word, like trade, comprehends every species of
         dealing in the exchange or passing of goods or
         merchandise from hand to hand for an equivalent, unless
         the business of relating may be excepted. It signifies
         appropriately foreign trade, but is not limited to
         that.

Traffic \Traf"fic\, v. i. [imp. & p. p. {Trafficked}; p. pr. &
   vb. n. {Trafficking}.] [F. trafiquer; cf. It. trafficare, Sp.
   traficar, trafagar, Pg. traficar, trafegar, trafeguear, LL.
   traficare; of uncertain origin, perhaps fr. L. trans across,
   over + -ficare to make (see {-fy}, and cf. G. ["u]bermachen
   to transmit, send over, e. g., money, wares); or cf. Pg.
   trasfegar to pour out from one vessel into another, OPg.
   also, to traffic, perhaps fr. (assumed) LL. vicare to
   exchange, from L. vicis change (cf. {Vicar}).]
   1. To pass goods and commodities from one person to another
      for an equivalent in goods or money; to buy or sell goods;
      to barter; to trade.

   2. To trade meanly or mercenarily; to bargain.

Traffic \Traf"fic\, v. t.
   To exchange in traffic; to effect by a bargain or for a
   consideration.

Source : WordNet®

traffic
     n 1: the aggregation of things (pedestrians or vehicles) coming
          and going in a particular locality during a specified
          period of time
     2: buying and selling; especially illicit trade
     3: the amount of activity over a communication system during a
        given period of time; "heavy traffic overloaded the trunk
        lines"; "traffic on the internet is lightest during the
        night"
     4: social or verbal interchange (usually followed by `with')
        [syn: {dealings}]
     [also: {trafficking}, {trafficked}]

traffic
     v 1: deal illegally; "traffic drugs"
     2: trade or deal a commodity; "They trafficked with us for
        gold"
     [also: {trafficking}, {trafficked}]