Definition: A duplex in real estate normally refers to a structure used for residential purposes and consisting of two living units with a common wall.
Real estate agents may list these properties for sale as either "residential", "mult-family" or "commercial", as they are purchased for diverse reasons. A family may buy one and rent out one side, which will be financed as a residential unit. An investor may buy one to rent out both units, thus financing it as a commercial property.
