The Collaborative International Dictionary of English v.0.48:

Negotiation \Ne*go`ti*a"tion\, n. [L. negotiatio: cf. F.
   n['e]gociation.]
   1. The act or process of negotiating; a treating with another
      respecting sale or purchase. etc.
      [1913 Webster]

   2. Hence, mercantile business; trading. [Obs.]
      [1913 Webster]

            Who had lost, with these prizes, forty thousand
            pounds, after twenty years' negotiation in the East
            Indies.                               --Evelyn.
      [1913 Webster]

   3. The transaction of business between nations; the mutual
      intercourse of governments by diplomatic agents, in making
      treaties, composing difference, etc.; as, the negotiations
      at Ghent.
      [1913 Webster]

            An important negotiation with foreign powers.
                                                  --Macaulay.
      [1913 Webster]

WordNet (r) 3.0 (2006):

negotiation
    n 1: a discussion intended to produce an agreement; "the buyout
         negotiation lasted several days"; "they disagreed but kept
         an open dialogue"; "talks between Israelis and
         Palestinians" [syn: negotiation, dialogue, talks]
    2: the activity or business of negotiating an agreement; coming
       to terms

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "negotiation":
   audience, bargaining, bargaining session, business deal, chaffer,
   chaffering, collective bargaining, coming to terms,
   commercial transaction, conclave, confab, confabulation,
   conference, confrontation, congress, consultation, convention,
   council, council fire, council of war, deal, dickering, discussion,
   exchange of views, eyeball-to-eyeball encounter, haggle, haggling,
   higgling, high-level talk, huddle, interchange of views, interview,
   meeting, negotiations, news conference, operation,
   package bargaining, package deal, palaver, parley,
   pattern bargaining, pourparler, powwow, press conference, seance,
   session, sitting, summit, summit conference, summitry, transaction,
   turn



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

NEGOTIATION, merc. law. The act by which a bill of exchange or promissory
note is put into circulation by being passed by one of the original parties
to another person.
     2. Until an accommodation bill or note has been negotiated, there is no
contract which can be enforced on the note: the contract, either express or
implied, that the party accommodated will indemnify the other, is, till
then, conditional. 2 Man. & Gr. 911.