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 WordNet 3.0 & Open English WordNet

In economics and finance, arbitrage is the practice of taking advantage of a difference in prices in two or more markets; striking a combination of matching deals to capitalise on the difference, the profit being the difference between the market prices at which the unit is traded. Wikipedia

Capitalisation of risk-free opportunities in financial markets Wikidata

A market activity in which a security, commodity, currency or other tradable item is bought in one market and sold simultaneously in another, in order to profit from price differences between the markets. Wiktionary

Market activity. Wiktionary (translation)