a number that was part of addresses, introduced in Boston in the 1920s, and used in many large cities from 1943 until the institution of the <#zipcode=ZIP Code> in 1963. The Zone number was placed between the name of the city and state. Example: Brooklyn 32, N.Y. The zone number helped facilitate the sorting and distribution of mail. A prototype of postal zones was attempted without notable success in Chicago in the 1890s.