A licensed individual or firm that charges a fee to serve as the mediator between the buyer and seller. Mortgage brokers are individuals in the business of arranging funding or negotiating contracts for a client, but who does not loan the money. A real estate broker is someone who helps find a house.

A broker is a party that arranges transactions between a buyer and a seller, and gets a commission when the deal is executed. A broker who also acts as a seller or as a buyer becomes a principal party to the deal. Distinguish agent: one who acts on behalf of a principal. The word "broker" derives from Anglo-Normandian brocour "small trader", of uncertain origin, but possibly from Old French brocheor "wine retailer", which comes from the verb brochier "to broach (a keg)". If it is individual, it refers to somebody acting as an agent for others, in terms of contract negotiation, purchases, or sales in return for a commission or financial reward.