The Collaborative International Dictionary of English v.0.48:

Barter \Bar"ter\ (b[aum]r"t[~e]r), v. i. [imp. & p. p.
   Bartered (b[aum]r"t[~e]rd); p. pr. & vb. n. Bartering.]
   [OE. bartren, OF. barater, bareter, to cheat, exchange, perh.
   fr. Gr. pra`ttein to do, deal (well or ill), use practices or
   tricks, or perh. fr. Celtic; cf. Ir. brath treachery, W.
   brad. Cf. Barrator.]
   To traffic or trade, by exchanging one commodity for another,
   in distinction from a sale and purchase, in which money is
   paid for the commodities transferred; to truck.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Barter \Bar"ter\, v. t.
   To trade or exchange in the way of barter; to exchange
   (frequently for an unworthy consideration); to traffic; to
   truck; -- sometimes followed by away; as, to barter away
   goods or honor.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Barter \Bar"ter\, n.
   1. The act or practice of trafficking by exchange of
      commodities; an exchange of goods.
      [1913 Webster]

            The spirit of huckstering and barter. --Burke.
      [1913 Webster]

   2. The thing given in exchange.
      [1913 Webster]

   Syn: Exchange; dealing; traffic; trade; truck.
        [1913 Webster]

WordNet (r) 3.0 (2006):

barter
    n 1: an equal exchange; "we had no money so we had to live by
         barter" [syn: barter, swap, swop, trade]
    v 1: exchange goods without involving money

Moby Thesaurus II by Grady Ward, 1.0:

105 Moby Thesaurus words for "barter":
   abalienate, abalienation, agency, alien, alienate, alienation,
   amortization, amortize, amortizement, assign, assignation,
   assignment, backscratching, bargain, bargain and sale, bartering,
   bequeath, bequeathal, brokerage, buy and sell, buying and selling,
   cede, cession, change, confer, conferment, conferral, consign,
   consignation, consignment, convey, conveyance, conveyancing, deal,
   dealing, deed, deed over, deeding, deliver, deliverance, delivery,
   demise, devolve upon, disposal, disposition, do business,
   doing business, enfeoff, enfeoffment, even trade, exchange, give,
   give in exchange, give title to, give-and-take, giving, hand,
   hand down, hand on, hand over, horse trading, horse-trade,
   interchange, jobbing, lease and release, logrolling, make over,
   merchandising, negotiate, pass, pass on, pass over, pork barrel,
   retailing, sale, sell, settle, settle on, settlement, settling,
   sign away, sign over, surrender, swap, swap horses, swapping,
   switch, take in exchange, trade, trade in, trade off,
   trade sight unseen, trading, traffic, trafficking, transfer,
   transference, transmission, transmit, transmittal, truck,
   turn over, vesting, wheeling and dealing, wholesaling



Bouvier's Law Dictionary, Revised 6th Ed (1856):

BARTER. A contract by which the parties exchange goods for goods. To
complete the contract the goods must be delivered, for without a delivery,
the right of property is not changed.
     2. This contract differs from a sale in this, that barter is always of
goods for goods, whereas a sale is an exchange of goods for money. In the
former there never is a price fixed, in the latter a price is indispensable.
All the differences which may be pointed out between these two contracts, are
comprised in this; it is its necessary consequence. When the contract is an
exchange of goods on one side, and on the other side the consideration is
partly goods and partly money, the contract is not a barter, but a sale. See
Price; Sale.
     3. If an insurance be made upon returns from a country where trade is
carried on by barter, the valuation of the goods in return shall be made on
the cost of those given in barter, adding all charges. Wesk. on Ins. 42. See
3 Camp. 351 Cowp. 818; 1 Dougl. 24, n.; 1 N. R. 151 Tropl. de l'Echange.