Most Americans know their ZIP code by heart. They type it into online forms, scribble it on envelopes and memorize it as part of their address. But not everyone knows the original meaning of the term.

Kept up to date by addenda. Vols. for 1992- issued in 2 or more pts. Available in a CD-ROM format. Also issued online with title: ZIP code lookup. Vols. for 1982-1983 were prepared by: the Retail ...

"New - larger United States zip code directory. Nearly 40,000 alphabetical listings of all cities ... including every station and branch post office. Revised directly from the latest National Zip Code ...

Today marks the 50th anniversary of the Zone Improvement Plan, the network of ZIP codes we use for everything from mail delivery to credit card security. The U.S. Postal Service began using the ...