arbitrage

from WordNet (r) 3.0 (2006)

arbitrage
    n 1: a kind of hedged investment meant to capture slight
         differences in price; when there is a difference in the
         price of something on two different markets the arbitrageur
         simultaneously buys at the lower price and sells at the
         higher price
    v 1: practice arbitrage, as in the stock market

from The Collaborative International Dictionary of English v.0.48

Arbitrage \Ar"bi*trage\, n. [F., fr. arbiter to give judgment,
   L. arbitrari.]
   1. Judgment by an arbiter; authoritative determination.
      [Archaic]
      [1913 Webster]

   2. (Com.) A traffic in bills of exchange (see {Arbitration of
      Exchange}).
      [1913 Webster]

   3. (Finance) the simultaneous or near simultaneous purchase
      and sale of the same or closely linked securities or
      commodities in different markets to make a profit on the
      (often small) differences in price.
      [PJC]