In the larger populated cities of the time, merchants found a way to cater to busy customers who had little time or energy to prepare food during the evening. The variation in Chinese cuisine from different regions led caterers to create a list or menu for their patrons.
ZIP Code began on July 1, 1963, as scheduled. Use of the new code was not mandatory at first for anyone, but, in 1967, the Post Office required mailers of second- and third-class bulk mail to presort by ZIP Code. Although the public and mailers alike adapted well to its use, it was not enough.
zip code. A code which was established by the United States Postal Service, for the purposes of identifying a location and routing the mail to that location. A zip code was originally 5 digits long, and now has been expanded to 9 digits for more detailed identification. The 5 digit zip code is still sufficient for sending all items of mail; the 9 digit zip code is used primarily by businesses as they sometimes get a discount for doing so.