A trade between two customers of a broker executed through the office of the broker who acts as agent in the middle, with the two customers acting as principals. It will usually be carried out at the midmarket price for the stock in question. The broker will charge both customers commission. Dresdner Kleinwort Wasserstein financial glossary
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A trade in which a single broker acts as the agent for both the buyer and seller. This can occur when a member firm simultaneously receives a buy and a sell order from two different customers but for the same number of shares in the same stock. When these orders reach the floor broker, he can easily cross them and complete the transaction, but only after going to the designated trading post for that stock and announcing the bid in case another broker is prepared to offer a better price. Exchange Handbook Glossary
Financial and business terms. 2012.