this article possibly contains original research
. (june 2017)
a 1973 stamp encouraging people to use the zip code on letters and parcels.
a zip code is a postal code used by the united states postal service (usps). introduced in 1963, the basic format consists of five digits. in 1983, an extended zip+4 code was introduced; it includes the five digits of the zip code, followed by a hyphen and four digits that designate a more specific location.
the term zip is an acronym for zone improvement plan; it was chosen to suggest that the mail travels more efficiently and quickly (zipping along) when senders use the code in the postal address. the term zip code was originally registered as a servicemark by the usps, but its registration expired in 1997.