ZIP Code

A ZIP Code (an acronym for Zone Improvement Plan) is a system of postal codes used by the United States Postal Service (USPS). The term ZIP was chosen to suggest that the mail travels more efficiently and quickly (zipping along) when senders use the code in the postal address.

Introduced on July 1, 1963, the basic format consisted of five digits. In 1983, an extended code was introduced, called ZIP+4 ; it included the five digits of the ZIP Code, followed by a hyphen and four digits that designated a more specific location.

ZIP Code is a trademark and ZIP+4 is a registered trademark of the United States Postal Service, which also registered ZIP Code as a service mark until 1997.