Množina: arbitrages

ETYM French, from arbiter to give judgment, Latin arbitrari.
A kind of hedged investment meant to capture slight differences in price; when there is a difference in the price of something on two markets, the arbitrageur simultaneously buys at the lower price and sells at the higher price.
Commerce, simultaneously buying stock, etc., in cheaper market and selling in dearer.

Množina: arbitrageurs

Someone who engages in arbitrage (who purchases securities in one market for immediate resale in another in the hope of profiting from the price differential); SYN. arbitrager, arb.
In finance, a person who buys securities (such as currency or commodities) in one country or market for immediate resale in another market, to take advantage of different prices.
Arbitrage became widespread during the 1970s and 1980s with the increasing deregulation of financial markets. The effect of arbitrage is to lessen or eliminate the price differentials among the markets. The term took on additional meaning with the increase in corporate buy-outs in the deregulated atmosphere of the late 1980s. Arbitrageurs speculated on target companies, buying stock and reselling it at the higher buy-out price.