A series of alphanumeric characters included in a postal address to help increase the speed and reduce the cost of mail delivery. Such codes are also used for profiling of housing price and area trends and to designate destinations in route planning software, as well as being used by gangs to delineate territory and as the lowest level of aggregation in census records. In the UK, post code data is stored, maintained and periodically updated in the Post Code Address File database, along with others used for commercial purposes.