The Collaborative International Dictionary of English v.0.48:

Vend \Vend\, v. t. [imp. & p. p. Vended; p. pr. & vb. n.
   Vending.] [F. vendre, L. vendere, from venum dare; venus
   sale + dare to give. See 2d Venal, Date, time.]
   To transfer to another person for a pecuniary equivalent; to
   make an object of trade; to dispose of by sale; to sell; as,
   to vend goods; to vend vegetables.
   [1913 Webster]

   Note: Vend differs from barter. We vend for money; we barter
         for commodities. Vend is used chiefly of wares,
         merchandise, or other small articles, not of lands and
         tenements.
         [1913 Webster]

WordNet (r) 3.0 (2006):

vending
    n 1: the act of selling goods for a living [syn: vending,
         peddling, hawking, vendition]

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "vending":
   consumer preference study, consumer research, consumer survey,
   direct-mail selling, hard sell, hawking,
   high-pressure salesmanship, huckstering, jobbing,
   low-pressure salesmanship, mail-order selling, market research,
   marketing, marketing research, merchandising, peddling, promotion,
   retailing, sales campaign, sales promotion, salesmanship, selling,
   sellout, soft sell, wholesaling