ZIP Code

A ZIP Code is a postal code used by the United States Postal Service (USPS). Introduced in 1963, the basic format consisted of five digits. In 1983, an extended ZIP+4 code was introduced; it included the five digits of the ZIP Code, followed by a hyphen and four digits that designated a more specific location.

A 1974 stamp encouraging people to use the ZIP Code on letters and parcels

The term ZIP is an acronym for Zone Improvement Plan;[1] it was chosen to suggest that the mail travels more efficiently and quickly[2] (zipping along) when senders use the code in the postal address. The term ZIP Code was originally registered as a service mark by the USPS; its registration expired in 1997.[3]