An individual who is paid a commission for executing customer orders. Either a floor broker who executes orders on the floor of the exchange, or an upstairs broker who handles retail customers and their orders. Also, person who acts as an intermediary between a buyer and seller, usually charging a commission. A "broker" who specializes in stocks, bonds, commodities, or options acts as an agent and must be registered with the exchange where the securities are traded. Antithesis of dealer.