The Collaborative International Dictionary of English v.0.48:

Retail \Re*tail"\ (r[-e]*t[=a]l"), v. t. [imp. & p. p.
   Retailed;p. pr. & vb. n. Retailing.] [Cf. F. retailler to
   cut again; pref. re- re + tailler to cut. See Retail, n.,
   Tailor, and cf. Detail.]
   1. To sell in small quantities, as by the single yard, pound,
      gallon, etc.; to sell directly to the consumer; as, to
      retail cloth or groceries.
      [1913 Webster]

   2. To sell at second hand. [Obs. or R.] --Pope.
      [1913 Webster]

   3. To distribute in small portions or at second hand; to tell
      again or to many (what has been told or done); to report;
      as, to retail slander. "To whom I will retail my conquest
      won." --Shak.
      [1913 Webster]

            He is wit's peddler, and retails his wares
            At wakes and wassails.                --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

retailing
    n 1: the activities involved in selling commodities directly to
         consumers

Moby Thesaurus II by Grady Ward, 1.0:

72 Moby Thesaurus words for "retailing":
   accouterment, agency, armament, barter, bartering, brokerage,
   buying and selling, catering, chandlery, consumer preference study,
   consumer research, consumer survey, dealing, direct-mail selling,
   doing business, endowment, equipment, exchange, finding,
   fitting out, furnishing, furnishment, give-and-take, hard sell,
   hawking, high-pressure salesmanship, horse trading, huckstering,
   interchange, investment, jobbing, logistics,
   low-pressure salesmanship, mail-order selling, market,
   market research, marketing, marketing research, merchandising,
   outfitting, peddling, preparation, procurement, promotion,
   providing, provision, provisioning, purveyance, reinforcement,
   replenishment, resupply, retail, sales, sales campaign,
   sales promotion, salesmanship, selling, sellout, soft sell,
   subsidization, subsidy, subvention, supply, supplying, swapping,
   trade, trading, trafficking, victualing, wheeling and dealing,
   wholesale, wholesaling